http://www.giltcity.com/national/virginamericafour
Main Cabin Select packs on sale.
Great if you know you'll need some short notice flights...
Otherwise at these prices it seems like it makes much more sense to buy cheap and pay upgrade costs.
2 pack:
Short $594
Medium $1146
Long $1942
4 pack:
Short $1134
Medium $2172
Long $3710