Might be a good idea to state your country. AFAIK, PayPal has no fees at all in my country, I assumed it was the same everywhere.

Can you get another bank account and card with no overdraft, and keep its balance near zero when not using it? When you buy, transfer the amount to the card and use it in whatever sketchy site you like. As long as its zero balance the rest of the time its relatively safe.

Payment card transactions can be disputed or reversed. Cryptocurrency transactions cannot be easily reversed. Reversal is an important capability because sometimes customers or merchants lie, or they can have problems fulfilling their obligations.

When the buyer and seller are in the same country, or are in countries with legal and criminal justice systems which cooperate, transaction risk is lower so fees can be lower.