reprint fee for textbook?

I have been approached by a US educational textbook publisher interested in reprinting my writing (about 4500 words total) in an undergraduate textbook. I have no idea how much to charge, I know this may not be the best place to post, but every DA XIA, anyone has some kind suggestions as to what would be a reasonable fee to charge them for reprinting my writing? Highly appreciate any recommendations. XIEXIE LA....