I think it's well worth the cost for quality shorts IMO. If I see shorts I like in my size, I buy them. I find with the smaller production runs for larger sizes, that if they're comfortable and have a decent cut then they'll usually get snapped up quickly.

Jerseys, on the other hand, are where I try to save a few bucks. I've been pretty lucky finding a few on the clearance racks at my local outdoor store(not biking specific: REI & Joe's, etc.) and from online discount outdoor gear vendors. If you don't mind not having a back pocket, then check out the tri/running stuff too. They might not be the cutest but I can usually find something I like. I remember someone, DarcyInOregon - I think(Hey,. what happened to her, anyway?), mentioning that they were able to find larger sized jerseys at their local Target too.