Have you talked to your doctor about other Herpes meds, such as Acyclovir? Valtrex is the newest, and while it's more convenient b/c you take it less frequently (I think), it is more expensive. Maybe taking Acyclovir (or another?) would be affordable.
Also, I don't know if this is an option, but I remember reading somewhere that someone got a prescription for a higher dose of the drug and then used a pill cutter to split the pills down to the dose they were supposed to take, and that reduced the cost. It might be something to look into.
One more thing, you might want to read up on the amino acid L-Lysine. There seem to be widely divergent opinions on use of this supplement, but I have read that some people use it successfully as a suppressive instead of the pharmaceuticals. I have not tried this, but there's a wealth of information out there. I'm sure you can find something.