My wife surprised me with a gravity feed box and 45 packs a couple of weeks ago. Tonight I decided to see how few packs I could open to put together the 130 card base set. I did it with just 28 packs, which is 8 more than the absolute minimum since you only get 1 of the chase set cards in each pack. I opened a few in frustration because I could see the sticker number I needed but I simply gave up trying to make out the back. So for $70, I got what I could've purchased on eBay for about $25. Chalk the extra $45 bucks up to the fun of opening the packs rather than just buying a complete set.
Since you can see the first sticker in each pack and by manipulating the cards, you can make out enough of the back to figure out if it's an A or B, that brought up an interesting thought. Has anyone put together a complete A and B set just from unopened pack fronts? It would be expensive, but it would be a cool addition to your collection. Then if you're really anal retentive, you could get the packs graded and perhaps have a PSA 10 complete set of unopened packs. Just a thought.