I'll say it plainly: quoting a low price for a Siemens PLC kit and then adding fees later is the fastest way to lose my trust. If you need to charge for engineering, shipping, or software licenses, put it on the quote. Don't surprise me after the PO is signed.
This isn't hypothetical. I've been an automation procurement manager at a mid-sized systems integrator for seven years. I manage a yearly component budget of about $245,000, and I've reviewed more than 150 supplier quotes in that time. The cheapest quote has almost never been the cheapest project.
Over the past six years of tracking every invoice in our procurement system, I found that 40% of our budget overruns came from two places: unplanned expedited freight and missing license fees. We now require all vendors to list these line items in their initial quote. That policy didn't eliminate the overruns, but it cut them by nearly half. I've also walked away from deals that looked slightly cheaper because the supplier refused to put license and shipping costs in writing. Usually, that decision saved us more than the discount would have.
Most buyers focus on the module PLC Siemens price per unit and completely miss everything that happens after the purchase order. Setup fees, expedited shipping, software licenses, and support contracts can add 30-50% to the total. From the outside, a low quote looks like efficiency. The reality is deferred cost.
Here's a concrete example. In early 2024, I compared two quotes for an S7-1500 starter kit. Vendor A quoted $4,850 all-in: CPU, power supply, digital I/O module, TIA Portal engineering license, and standard freight. Vendor B quoted $4,320 for exactly the same hardware, but the license was an extra $930, and guaranteed shipping was another $280. When I totalled it, Vendor B came to $5,610. Vendor A was $760 cheaper, and it had a shorter lead time.
That's a 17% difference hidden in line-item omissions. It wasn't malicious—it was just how Vendor B structured pricing. But my budget didn't care about intentions. The same kind of omission shows up in 'economy' modules that don't come with documentation or basic support access.
I have mixed feelings about the 'race to the bottom' in industrial parts. On one hand, lower component prices open doors for smaller integrators. On the other, someone always pays for the margin—usually in service, warranty, or quality. That's why I've stopped treating unit price as the main metric.
The suppliers I stick with are the ones who send a one-page cost breakdown without me asking. They tell me exactly what's included: firmware version, license, warranty, return policy, and minimum order quantities. That transparency is worth money to me because it lets me plan without surprises.
I still kick myself for choosing a vendor based on unit price alone back in 2022. That decision cost us $2,100 in extra engineering time because their PLC module documentation was incomplete, and their support line was only available during hours that didn't match our shift. If I'd asked for a full cost breakdown, I could have seen the weak spots before we signed.
When a machine goes down, the first thing I grab is a small Fluke multimeter to trace the fault. That 30-minute diagnostic is when I really appreciate a vendor who answers the phone—not one who disappears after the invoice is paid. You can't test a vendor's hidden fees on a bench.
I'm not saying every cheap part is dangerous. A third-party Samsung stove control panel might work fine in your kitchen. But a safety-rated industrial loop is different. A PLC that talks to a light curtain or an emergency stop needs to be certified for that environment, and the module you choose affects that certification.
Here's a parallel I use with my team: there are forum posts about connecting a generator to your house without a transfer switch. Most electricians will tell you it's dangerous—it can backfeed the grid and kill a lineman. The same logic applies to PLC modules. A shortcut in a safety function doesn't just risk a repair bill; it risks a life. That's why I check for IEC 62443 compliance before I compare prices. As of January 2025, you can verify module certifications in the Siemens Industry Online Support portal.
I know, this sounds dramatic for a procurement blogpost. But I've seen what happens when a non-certified component gets installed in a safety loop. The customer had to re-engineer the entire panel, and the module ended up in the trash. The 'savings' on the cheap part was nowhere close to the rework cost.
I get it. When cash flow is tight, every dollar counts. I've sat in budget reviews where the boss asked why we were paying $200 more for a module from Supplier A when Supplier B was cheaper. My answer was the spreadsheet: the 'cheap' module required two extra days of engineering time because the documentation was incomplete. That ate $1,800 in labor.
To be fair, I'm not 100% sure every expensive module is justified. Take this with a grain of salt: I've seen premium parts behave just as badly as budget parts, and I've seen budget parts outlast the expensive ones. That's exactly why I calculate total cost of ownership instead of guessing.
My TCO formula includes purchase price, engineering time, potential rework, downtime, and the cost of a supplier who disappears when you need help. Usually, the transparent supplier wins that calculation—but only because I have all the numbers on the table.
These days, my RFQ always includes one question: 'What is not included?' If a vendor hesitates, that's a red flag. If they send a detailed list, they've earned the right to compete.
A good quote names the exact hardware, firmware version, license type, freight terms, and warranty period. A bad quote says 'price available upon request.' I've learned to treat that phrase the same way I'd treat a missing specification: it's a warning.
I also ask for the same scope from at least three suppliers. Not to grind them down to the lowest number, but to see who's comfortable sharing their cost structure. The supplier who lists all fees upfront—even if the total is higher—usually ends up being the cheapest in the long run.
So no, I'm not hunting for the lowest Siemens PLC kit price anymore. I'm looking for the lowest total cost, and that starts with transparency. Give me a clear invoice, and I'll give you the order.