Blue Jeans was a weekly girls' comic/magazine published by DC Thomson from 1980 to 1991. It contained photo strips alongside features on pop music, fashion and "readers' true confessions". Great nostalgia.
Issues pop up on eBay UK and sell for a couple of pounds. I saw a first issue with no free gift sell for £19.99. With free gift I would expect it to fetch anything up to £50 for rarity value.
Note: some PR issues may have no value. Selected issues in FN, VF or VF/NM may not exist in some titles.