The bazaar is a private market that exists within your warband.
The market refills faster with more land and camps (or foragers, for buying food).
Camps account for 70% of the cost reduction. Markets account for the other 30% of the price reduction.
Minimum price is 70% of the base cost, modified further by any racial bonuses.
You can sell up to 75% of any type of troop at once. (Percentage sold is recorded and decremented by
1% * (1 + markets / land)
every 10 minutes.
Max checkboxes are those little boxes next to the troop amount fields. These allow you to buy/sell the maximum amount allowed for that troop or food. Use these when you need to buy large amounts, or are in too much of a hurry to type in a bunch of numbers.