I agree about not spending lots of $. Below is a good link to drilling/replacing with stainless steel screws.
I have a pair of 5000s that has about six studs on each sandal using this method. I've managed to get a full season at Montauk with them. I also have a brand new back-up pair that I have greased all the studs. When the first pair doesn't work for me anymore I'll be ready with a new one.
Korker Modification - Making Korkers that last!