need help with sub/center

marms

so i picked up a pair of R50's in the fall and im wanting to put together a nice setup. i was wondering if certain speakers went better with the R50's or what people would recommend for center speakers, sub, and rear speakers. being a college student, im a little low on funds so im fine putting my setup together piece by piece and i feel that a sub would probably be the next on the list. i was thinking about either the psw110 10" or psw505 since its cheap at newegg (although i would really like the cherry finish).

if anyone has any suggestions on subs or center speakers, it would be greatly appreciated