I rarely finish a product and its even more rare if I purchase it again because I'm always trying out different things. I'll start using the product for a few weeks and then the novelty wears off, but below are products I've finished and re-purchased:
Nivea Lip Care Pearl and Shine £2-£3 depending on the store. I have so many lip balms and this is one of the only ones I've stuck to. Firstly, because its a stick lip balm which means my hands won't get messy. Secondly, it makes your lips smooooooth and thirdly, leaves your lips with a gorgeous pearly shine.
Collection 2000 Volume Sensation £4.99. Although I do use different mascara's, this is the only one I've re-purchased (about 6 times). I love my mascara's to have large bristle brushes and this has exactly that.
Boots Intensive Hair Masks £1.99. I use these everyday as a normal conditioner so no wonder I go through so many! They leave my hair silky soft :) Review for these can be found here.
Body Treatment Cocoa Body Butter (Have only found in Wilkinsons) around £1. I've written a review for this here. Smells gorgeous, leaves skin really soft, same size as a large Bodyshop's body butter and is extremely cheap!