i'm not sure how much the lanes are, so i'm gonna list the prices of pairs of shoes so you can just add the price of the lanes and find the answer:
1 pair - 2.95
2 pairs - 5.90
3 pairs - 8.85
4 pairs - 11.80
5 pairs - 14.75
6 pairs - 17.70
7 pairs - 20.65
8 pairs - 23.60
(thats the highest amount of shoes he could get)