self-employment income is subject to two federal taxes: income tax and self-employment tax
if this is your only income, you are required to file a return if the net income from these jobs (self-employment) is $400 or more. there won't be any income tax because you get a standard deduction at least equal to your net SE Income, but you'll owe SE tax of 15.3% on 92.35% of the net income (effective tax 14.1296%
If you had expenses incurred in earning this income (like postage or other direct costs) they can be deducted on Schedule C.
there is only one form the 1040 and there will be schedules C and SE.
charitable contributions will not benefit you if this is your only income. they're not deductible on Schedule C and the net income for income tax purposes would be offset by your standard deduction
