I personally can't use 99% of the primers in the market because they're silicone based. My skin is oily & breakout prone. The only primer I've found which helps my makeup stay in and helps prevent oil breakthrough is Nurturing Force Blot Out Offensive. The stuff is amazing. If your friend is interested she can find it at Camera Ready Cosmetics online. As far as foundations go, she should be using the correct moisturizer under her foundation. Brand has nothing to do with it. If her foundation is water based, then her moisturizer should be too. The best foundations I've found that work on my skin after a lifetime if trial & error are Estée Lauder Double Wear (it really stays & covers well), Maq Pro 6 pan foundation palettes (also can be found at Camera Ready Cosmetics) and Monave Liquid Matte cream foundation (as well as their mineral foundation/concealer). None of them break me out (Monave's actually helps heal my breakouts), they last really well on oily skin & none of them feel heavy once applied. You can also get lighter to full coverage with all of them with a little bit of experimenting, depending on a person's needs at any given moment. I also love all of them because they're 'all in one products for me', meaning they work as concealers & foundations for me. The Maq Pro palette also works as a contouring product & highlighter for me. Which winds up saving me money in the long run. Monave's products are the most economical but are incredible products, while Maq Pro is $42 for a HUGE amount of product, and Estée Lauder Double Wear about $38-$45 per 30ml/1oz depending in which country you're in.