I spotted one that looks decent and I can get it pretty reasonable compared to what they are going for...  what should I look for and any issues?  thanks...

Original or the A1?

Only thing I have to contribute is tha Sig doesn't support the folded slide guns anymore. 

the A1

By today's standards, the folded slide SIGs might be called obsolete. But, SIG still support/service them guns.

Other than the obvious cracked or broken parts, check the slide to frame rail fit. A little movement is fine, but if you can hear it rattle when shaken, that's not a good sign. Also check the frame rails. There should be no chips or gouges. Look down the barrel with a light checking for rust, nicks or scrapes.

That's about it. It's a good idea to put a spring kit in if you don't know that last time they were changed. Not sure there is an actual kit for the p225, but change the decocking lever spring, slide catch lever spring, trigger bar spring, recoil spring, and the slide pins (the ones that hold the breach block in) and if it were me I'd change the firing pin spring since I had the breach block out and it's inexpensive.

I was able to pick up a factory CPO with threaded barrel and tall suppressor sights for $700 a few months ago. It is about the size of the P229 but a bit thinner, being a single stack. It fits my hand quite nicely and handles the suppressor with no problems.

Very happy with it.

I had a folded slide model years ago and they will last a lifetime,if you do the proper maintenance-springs,lubrication,etc.. I don't know much about the newer models but if they are anything like the older ones, they are a keeper. The only thing about it you might consider is that it is  not much thinner than a double stack model like a 228 or 229. If you live in a state where capacity is a factor then the 225 is for you.