I have a ~$150 Bissel cleaner. I mix hot water, carpet cleaner stuff, and a little OxyClean (or liquid hydrogen peroxide, same stuff). Works well on carpets that are dirty, but not heavily stained. If they're really stained, I don't think it would be all that much more money to just replace them vs hire a pro cleaner. Maybe spliut the difference. Buy the $150 home Bissel, use it, get 1-3 more years out of your existing carpet, and start budgeting/saving to replace it then??