Don’t know if you have a Trader’s Joe in your neck of the woods or not, but they sell a lot of good wines for under $10, from all over the world. Even their house brand that sells for under $3 is fairly drinkable (Charles Shaw, or Two Buck Chuck as it is popularly called). The only problem is often times I find a wine I really like a lot , but it always seems to disappear from the shelves forever shortly afterwards.
For your real bargains, try some of the dollar stores in CA.
Quite often they have remarkably good wine, presumably stuff that just didn’t sell well for some reason.