10mm is great round. If it's a carry gun and you have no time on it youll need quite a bit of practice as it is not a falt shooting round. it HOPS .
As far as ammo check this joint out http://www.underwoodammo.com/10mmauto.aspx
25/ per box of 50 for the ball ammo in any gr except 200 thats 27.50 not too bad and their carry ammo is a bit more but it;s the good stuff. Starline brass , GD bonded , xtp , or some generic hp they even still have a few boxes of golden saber left < my personal favorite 10mm round >
If your poor I dont think I'd get a 10mm but if your anything other than poor its affordable , just a bit pricey. good luck