I get my sun care stuff from Avon although I do buy the Piz Buin All Day Protection Cream to put on in the morning before I leave the apartment. Then top up with factor 15 creams throughout the day.
I have long hair and I use a spray for sun/heat protection (got my last lot from Avon but not sure if they still do it). I put my hair up during the day and always wear a hat (even though I dont really do hats !). I then wash my hair on an evening.
I purchase most of my holiday toiletries from the supermarkets. Taking advantage of any 2 for 1 offers and putting one away (I actually dont go on holiday myself until September but I have already started buying bits and pieces to put away). Clothes come from wherever. Peacocks do lovely vest tops in packs of three. Primark is also good value for bits and pieces (but thats another thread!), I get my swimming costumes from M&S because they do classic lines that flatter and cater for my size. I also buy my T shirts there. George at Asda is brilliant for going out tops and trousers/skirts and mens stuff at great value.
I think you have to shop around and choose the best bargains. I like to start preparing early. That way when my holiday comes around I have everything I need and dont need to find extra money to buy stuff.