Planning to buy an iphone for an xmas gift. Should I get a 3GS?

I have about $150 to buy an iphone for my husband to use on Tmobile's network, so it has to be unlocked, and I prefer factory unlocked over jailbroken.

I was planning to get a 3G or 3GS, but have recently seen some reviews that current apps don't work at all, that the unlocked iphone 3GS is unable to access the high speed Tmobile networks and is stuck at slow speeds, can't update OS, etc.

In a world where I had $500+ to spend on him for xmas I'd buy a 4 or maybe even 5, but we're totally budget. Is he going to be unhappy with the quality of the phone? The access to the network? Will it still function as a hot spot for other devices?

I have a 3g and husband has a 3gs. Both on tmobile. Mine is absolutely awful. His is a tiny bit better. But if you have ever had an Iphone 4 or higher you will definitely hate it. It just isn't the same quality. My 3g is basically a paperweight. It only works 1/3 of the time. :/
I can't even try to set mine up as a hotspot but that's because I live in an area with super slow internet!

Buying a 3GS would be a waste of $150. Spending money on phones that are 4 years out of date is a poor way to spend money if you are on a budget. If money is that tight you should be asking yourself whether this is something you should be spending money on at all. Smartphones are luxuries, not necessities. Personally I would start combing craigslist for a 4s or even a 5 with a broken screen. Buy it on the cheap and have the glass repaired.

If at all possible I would try to get an iPhone 5c on T-Mobile. Since the goal is to get one on T-Mobile, unlocked (or even if it was to be unlocked to get on T-Mobile)

http://www.t-mobile.com/...ne-5c.html

As far as the 3GS

-apps will work depending on what version of iOS they need at minimum. Most should still work as iOS 4.3 is considered that minimum, the 3GS runs up to 6.1.3
-iPhones in general can't access 3G (no 4G at all since it was not a 4G phone) because of the frequencies used in the iPhone vs T-Mobile. Remember at the time T-Mobile was not an official iPhone carrier.
-iOS 6.1.3 is the last version of iOS it could run

3GS is a little outdated today, I would recommend getting 4 or later. 4S is free on a 2 year contract, I would go that route.