Alright Fella, I recommend 14oz gloves for sparring, for your protection and for your partners protection aswell.
someone above recommended 8oz gloves, well i can take a hit or two you know but i dont wanna be getting hit by someone wearin 8oz gloves during a training session.
The weight will also improve your speed whilst punching as if you're constantly hitting the bag/sparring wearing heavy gloves then come competition time you put some 8oz gloves on you won't feel the weight asmuch.
As for the gym, they seem pretty unhelpful not saying what equipment to buy until you give them money, i wouldn't train there at all.
Me personally I use cheap bag mitts when hitting the bag, never feel discomfort and alot of times ive hit the bag without any wraps under the mits. I aint suggesting you do this im just saying i have no problems.
I dont use my 14oz gloves for the bag, as the cost me £45 ($80) and wanna keep em in good shape as poss for sparring and stuff, bag mitts you can pick up from your local supermarket lol.
Gloves i recommend?
I'd be careful of where you buy stuff from though as gloves particularly have alot of fakes around so if your in the states order your Twins from http://www.fightstuff.us/catalog