Mac's suggestions are good; you can basically just go for anything that's cheap. There are loads of cheapo/off-brand locks out there aswell, and most are very good for beginners. Not saying they're all easy, but when your fingers get used to everything you'll see what I mean.
Repinning is a handy skill to have, but the more locks you have to pick the better. Repinning a lock will change the bitting (and the binding order if you swap the drivers around), but it's wise to have as wide a range of locks to hand as possible... they all have their own little quirks. Swapping pins around doesn't really change it that much, unless you change the bitting to something really extreme anyway. Having a mixture of old and new locks is a good idea aswell, as the feedback in older locks generally isn't as crisp.
Good luck
