Drywall Primer

Here I was cruising through Home Depot and in the paint dept. I saw a Glidden drywall primer - a 5 gallon pail for $34.47. I've just finished installing 92 sheets of drywall. Still have to tape and mud. Anyone used this stuff before? I still plan on gettig the flat and some eggshell from either Duron or SW but what the H**L for this price how could I go wrong? Actually that is what I want to know. LOL. As far as that goes, what about a top coat? I got a bit of sticker shock late yesterday afternoon. I get a contractor's price on paint but the guy at the counter quoted me @ $30 per gallon (Ultra Delux) for flat & @ $31.50 for eggshell. Thanks.