mkV arron is correct on the # of cards outstanding and what lenders see as risk. but you have to also consider the utilization part of credit too. think of it this way... say you have 2 credit cards, both with $100 limit. and you charge $50 bucks on card 'A'. Now you are 25% utilized. now based on aaron's orig post, you close card 'B' because you are trying to get a re-fi on your home and want as much avail to yourself as possible. Well instead of being 25% utilized you are now 50% utilized, which is BAD. try and keep it under 30% for that top tier credit score...
for the OP, it would cost you less in interest to pay every week a little bit, than save up and pay a big chunk (saying the two amnts would be the same). CC's do charge on an average daily balance, so the smaller that figure is, the cheaper it is for the consumer. also you want to pay as early in the billing cycle as possible. if you can't pay the full stmnt bal every month to avoid all finance charges, try paying 10% of bal. if not, then pay min + finance charges, and last if those two aren't an option pay at least the minimum.
Paying the min and then another pymnt doesn't put the pymnt directly toward the principle. Payments are allocated as the following... the first part of you payment goes towards any fees and finance charges, then towards the lowest interest rate balance (good info for you 0%-ers) and then up to the highest rate and so on. this brings up an interesting point. if a card will not charge you a 3% fee there is some sort of catch to it, maybe your purchases are at a higher rate so you are paying interest on purchases but not your initial transfer, or they will bang you with all that back interest if you don't transfer it out b4 the promo period ends, or something else...
just be careful, keep the balances low (I know times are tough), keep those pymnts coming IN TIME!!! and life of loan transfer options are almost ALWAYS a better deal and less hassle than limited time offers for balance transfers if pying a large amount back that will take you over 1year.