Hi there -- Thanks for your question. I'm honestly not trying to be glib, but the cheapest solutions I can think of are (starting with the least expensive):

1. use fewer / thinner blankets
2. get a box or pedestal fan (either pointed at you or just circulating the air in the room)
3. install a ceiling fan
4. BedJet (a cooling mattress pad that works with an air pump)
5. ChilPAD (a cooling mattress pad that works with a water pump)
6. turn up the air conditioning

If you were expecting there to be something you can add to your bed to make it cooler, the only things on this list are #4 and #5, however they will generally cost $400 and up, so they may not be something you consider "cheap."

Notice that although a search on Amazon for "cooling mattress pad" will reveal tons of other options, I did not include these because in general I think that without some sort of pumped cooling mechanism, surface applications will not have a very significant impact in offsetting the heat issues you're having. Also note that any mattress pads or protectors that claim to cool you by using gel memory foam will almost certainly NOT have a net cooling effect.

I hope that's helpful.