Reseal, repair or replace stamped concrete
If your stamped slab looks dull or soaks up stains, it usually needs fresh sealer rather than anything bigger. If it has sunk, tipped toward the house or cracked through in many places, the base underneath has usually given way, and I'll tell you honestly that tearing it out and pouring again on a proper base is the better use of your money.
What shapes the cost of stamped concrete
Size matters most, then shape, since curves and steps take more forming and handwork. Tearing out old concrete, hauling it away and fixing poor ground all add to the bill, and a busy pattern takes more time than a simple one. If the budget is tight, I'd sooner simplify the pattern than skimp on the base, because the base is hidden on day one and it's the one part you can't fix later without starting over.