Most countries have their own law about paying taxes on casino winnings. If you are not sure of percentage or limits on tax deduction on winnings, please ask your local tax authorities.
If you want more control over how much you play for, it might be a good idea to invest in a Paysafecard. This is a prepaid visa card where you choose how much you want to refill. Otherwise, Skrill and Neteller offer fast and secure solutions without being directly linked to your bank account.
Most of them support Euro, Pound, and Dollars as currencies on the games. They also offer other currencies as well like Scandinavian currencies. Some even support crypto like Bitcoin.
Casino has to have wagering requirements or other restrictions to be able to offer bonuses to all. If it was possible to get free money without restrictions, even the biggest casinos would disappear quite quickly. Therefore, wagering requirements ensure liquidity at the casinos, giving more players the opportunity to get more money to play with.