You probably could have seen a vet for not much more money than these three over the counter meds that have not worked. There are certain things with our pets that we should never attempt to go the "cheap" route and worms are one of them. Find an ASPCA or similar organization in your area that charges on a sliding scale or a mobile pet hospital in your area that is about the least expensive vet one can find. If you don't take care of this now, the amount of money you may end up spending on getting this taken care of could be quite high indeed.
there are several kinds of worms dogs can get... not all are treated with the same medications. How do you know your pet has worms? Have you seen them? What do they look like? Tape worms for example need to be treated with a different medication than do most other worms (Roundworms and Hookworms) and treating for these worms 10x will not get rid of tapeworms.