Make Up Forever makes one hell of an amazing primer. Goes on nice and smooth and helps to even out the skin for foundation application 
You probably want to look for an oil free foundation. Right now I'm using the Hello Flawless Benefit foundation. It has sunscreen already in it which helps me eliminate one extra step from my foundation routine. It also has vitamins E and C which is great if signs of aging are a concern (I'm only 23, but I appreciate anti aging products) There are only 9 shades to choose from, but as someone who usually has a lot of trouble finding foundation that matches, I didnt have a problem with this foundation.It is a demi-matte foundation so it depends on whether you like a glowy look for your face or more of a matte look. If you prefer Matte, NARS makes a great sheer matte foundation. Both these foundations are in the $34-$40 range, but I feel that when it comes to foundation, you should be willing to splurge a little as it is going on your skin! But also with the price tag, you want to make sure you get the correct shade. Feel free to go to ulta or sephora as they will shade match you for free. Go up to one of their associates and let them know what you're looking for in a foundation, the kind of look you're going for (matte vs demi matte etc..) as well as what coverage you want. They will take it from there!
EDIT: If you have extensive scars you have two options, The first and more preferable option is that you invest in a concealer. Doesn't have to be too expensive (I use a $8 one from Rimmel) but with concealer you can apply it before foundation only on the troubled scared areas and it will prevent you from having to apply multiple coats of foundation all over just to cover up scars. The second option is to get a foundation with a high percentage of pigment. Kat Von D's foundation the lock it tattoo has 21% pigment which is seriously high. The foundation is pigmented enough to even cover up tattoos! I tried it as i have some PIH but I quit using it as I found it to be a little heavy. For special occasions though, it would be a great foundation.
Good luck.