While installment loans for bad credit do cost more than many other loans simply because the interest rates are higher, you shouldn't have to worry about extra fees and surcharges if you meet your loan payments on time. On your payment due date, your lender will either need an in-person payment, or the amount owed will be withdrawn automatically from your bank account.
If you don't have enough money in your account to make the payment (including the interest), you can expect to be charged a non-sufficient funds (NSF) fee by your bank. Your lender will probably try to withdraw the money you owe a few more times, and each attempt will incur another NSF charge from your bank — all those bank fees can add up quickly.