Personally I prefer to use shampoo, conditioner and styling product from the same range as they're designed to work together. Given comments on this thread though OP, you could maybe try a cheaper shampoo, then a conditioner and styling product that match.
Sebastian: very good but very expensive and not always easy to get hold of
Paul Mitchell: good and not too expensive
Bumble & Bumble: brilliant but expensive. They have a curl range that allows for different thicknesses of hair that I really like
TiGi Honey and Oatmeal: not as good as B&B but better value for money
Redken: haven't used it for years. Was always good though
Fudge: great, not always available
KMS: bleurgh. Never got on with it. Bottles are stashed somewhere as my emergency supply when the rest runs out
Phytospecific: over priced and over rated (IMO)
Label M: my current favourite
Look for things with silk in as well, they can be good. If there's a TKMaxx near you it may be worth rooting around in their supplies. Otherwise I tend to order over the internet, but then I live in the sticks, not near hairdressers that stock decent stuff.