considering how long a set of pool balls lasts, if you play enough hours it only makes sence to buy good ones, sometimes you can find a set of tournment used balls (so they have like 20-30 hours play on them-basically nothing) for $150-$175 here in the For sale section.
the cheap balls play bad and are a total waste of $$$, i have some-I like to experiment with everything. dont waste yur $$
the mid level balls that are 100-150 new play ok.
the good ones that retail for over $200, to $250 play the best but like I said can be found for around $150 here from time to time and thats your smartest play is to find some like that, I sold off 20 sets a coule years back.
I have some real old good balls in storage that I cant get to that are worth less than 100 because they dont look so good, the colors changed over the years but I weighed them and measured them they are all within the specs of new balls and play like new balls. they might be worth $75 but play like $250-problem is I have zero chance to get to them. Sorry.
just keep checking here and you'll find some Centennial or Aramith balls that are slightly used for $150ish and you'll be set. Dont pay $300 for them brand new-its not worth it.