Since losing weight I have started feeling alot more confident in myself and have started wearing more makeup than I used to and I LOVE it

Im not really sure where to start with alot of things though... after reading rave reviews I want to try a primer? I have had a few issues with my foundation not going on as smoothly as it could, and not lasting as long as it could.
All good and well... but when I go to buy one, I have A MILLION choices!! Where do I start?
I need something at a reasonable price, and easy to use!!
Ps Im from the UK... If that makes a difference for shopping?
Thanks xx