There are a couple of fee structures. This, from IRS' Instructions for Form 9465:
Installment agreement user fees. We charge an
installment agreement user fee to set up an installment
plan. The amount of the user fee can vary depending on
whether you set up an installment agreement online or
agree to pay by direct debit. The fees are:
- $31, if you set up an online payment agreement and
make your payments by direct debit;
- $107, if you don’t set up an online payment agreement
but make your payments by direct debit;
- $149, if you set up an online payment agreement but
don’t make your payments by direct debit; or
- $225, if you don’t set up an online payment agreement
and don’t make your payments by direct debit.
Reduced installment agreement user fee. You may
qualify to pay a reduced fee of $43 if your income is below
a certain level. The IRS will let you know whether you
qualify for the reduced fee. If the IRS doesn't say you
qualify for the reduced fee, you can request the reduced
fee using Form 13844, Application For Reduced User Fee
For Installment Agreements. You can qualify for the $31
fee if you set up an online payment agreement and pay by
direct debit.
Form 13844, Application For
Reduced User Fee For Installment Agreements