for the average 'joe' you won't have to worry about 'taxes' at all. However sportsbook manager's are required to fill out a 'form 8300' for cash wagers over $10,000. Not all do it but most of the reputable books will have someone monitor those that routinely wager large amounts. If you place a wager i.e.; $16,500 to win $15,000 (for example Baltimore Ravens -3 :SIB )and if the ticket wins.. the sportsbook does NOT take out one penny for taxes. You will get $31,500 hard cash.
At the end of the fiscal year the book(s) will report to the IRS your wagering activity, wins and losses. They just report it, it's up to you to itemize it with your tax return. accountants will offset the wins with the losses along with the rest of your income/deductions. It's no different that declaring stock market gains or losses in a fiscal year.
for the recreational bettor just stay under $10,000 collectively for a 24 hour period and you should be fine. also move around to different shops
