I bought an inexpensive one on Amazon during a sale this fall. On our way back from a trip, I intentionally pulled over and let out 15 lbs of air a couple miles from home. The TPMS immediately recognized the lower pressure, giving me some confidence.
My next RV will have a more expensive system with the internal style TPMS. We're going to take that cross country for a long trip, I want the peace of mind. Lots of people like to poo-poo TPMS systems and say they are worthless, but I disagree.
I've seen plenty of stories of people that had a tire fail and they didn't know for a while. The tire kept deteriorating as it was driven down the road and damaged the trailer too. I have 2 people that we camp with that this happened to. Tire failure and they didn't know until chunks started flying and people starting honking at them and frantically pointing to the trailer.
Even if my TPMS does nothing but alert me before additional damage is done, it is money well spent. We do several longer trips a year. I'll check tire pressure in the morning before we leave, then I don't check again until I get to a fuel station or the next destination. Plenty of time and miles for a road hazard to cause a slow leak that develops into a big problem if left unchecked.
