What are some cheap ways to keep one's bed cool while sleeping?

I really need some way to sleep with my weighed blanket without turning into a microwaved Hot Pocket.

@jaycie Some things I've found to help for me, depending on situation and ambient temperature:
- Drape just the *edge* of the blanket over me, so that there's an open gap on the side (but my feet are still covered) - still weighted, but not enclosed
- Point a fan directly at me, it really does seem to help even though I don't *feel* the airflow through the blanket
- During colder months, keep my window slightly open to deliberately cool down the room, but not too much (or my body starts overcompensating and sweating)
- Switch to a buckwheat pillow; they take some getting used to, but they ventilate *exceptionally* well, and (at least for me) it actually affects the temperature control of my whole body!

Ultimately the single biggest factor for me turned out to be my choice of mattress; specifically, switching to one that ventilates well. But that's comparatively expensive (though particularly Lidl often has good well-ventilated options that are cheap by mattress standards; avoid foam options unless they specifically have ventilation holes)