I think foundation is impossible to recommend if you don't know the persons skin type and/or are quailifed to to some degree, but I would suggest setting spray if you are not already using it. I use it either with, or instead of setting powder, but I always use it. I used to buy Urban Decay for about £30, I think, but then I switched to Makeup Revolution, which I think is about 6. Not sure if I noticed a difference.. I now get the sports one thats supposed to hold up better, but again, I can't say if it is or not.
I have oily, acne skin which is kept clear by use of good prescription medication, also I am in my late 40s so slightly ageing (but not so much thanks to the oily/acne/medication). I have to avoid anything which clogs pores, because that will override the medication effect and I will break out. I have to mix and match because if I use all oily skin products it is too much, ends up cakey and flakey.
I have a range of moisturisers, find that normal skin moisturise, normal skin primer followed by good concealer (Clinique 24 hr), then a matte foundation, powder, matt setting spray works the best.
If I am wearing tinted moisturiser/normal foundation only then to I use a matt primer.