I want to extract carotenoids, but want to use some inexpensive method. can you suggest me some method?
It depends on what your raw-material is, and what you want to do with the extract. Carotenes are only soluble in very non-polar solvents like hexane and acetone. I have not worked specifically with carotene, but some years ago I had to analyze some xanthophylls, and during that, I experienced that they were pretty soluble in vegetable oil (I think it was rapeseed oil). You could try this, but off course it leave you with the problem of how to get rid of the oil :-)