SheWho
I'm 79 and have used a cheap primer with no makeup on top. I got compliments. The more you put on, the more awful the skin looks.
I agree, I usually wear very little on my skin as it can make me look as if I'm wearing a mask. If I'm making more of an effort for a special occasion I use a light concealer in the correct colour where necessary. As I have dry skin I find that makeup including powder eyeshadow will stay put without primer and I use a mascara that doesn't smudge.
When I was younger I always used MAC or Laura Mercier primers which worked all day, but these are obviously outside the £10 price range - worth it for me when I was too busy to check my makeup though.