Just last week I posted a break of a box of 1990 Bowman. I actually bought three boxes. On average, each box cost $3.97 plus $3.00 s/h. The first box left me 140 cards short of a set, so I figured I’d open another box and see what comes out.
Stats
base cards: 380 of 528 – 73.5% complete (124 duplicates)
Art Inserts (1:1): 11 of 11 – 100% (25 duplicates and higher)
Base cards
Base cards are base cards. The previous box post shows some cards. The one notable card I got in this box was Sammy Sosa, one of the key rookies in the set. Sosa is just about unrecognizable. I wonder if he could selectively forget how to speak English all the way back in 1990.
312 Sammy Sosa (unrecognizable & I’m not sure I ever knew that he started out on the south side of Chicago)
Conclusion
This box was just about on the money with the first. The first gave 388 different card; this one gave 380. Based on a little math, the first box gave 73.5% of a set, and the second box gave 72.0%.
The two boxes together (if random) should give almost a complete set – 528 cards. How complete? Here’s the formula for the number of cards not found between the two boxes.
missing cards = 528 * (1 – 0.735) * (1 – 0.720) = 39 cards (39.2)
If the two boxes in fact left only 39 missing cards, then that would be 489 different cards. What did I have after opening both boxes? – 451. That’s not quite 489, but it’s not terrible.
I have a third box of 1990 Bowman that I’ll probably open and see how close I can get to a complete set.

Where did you get the boxes from?
The ebay seller was kearheat. He’s not listing any now, but with a little patience, you should be able to pick up a few boxes at a good price.