You report every dime that crossed your palm as gross receipts, whether on a 1099 or not. You deduct every dime you paid out that was reimbursed as part of the payments that went into the gross receipts figure. You should end up with the figure that equals the total of the fees and bonuses.
(You got $100 in fees plus $50 in reimbursements. Report $150 as gross receipts, deduct the $50 from that, to end up with gross income of $100. Then you deduct your mileage and other expenses from that figure.)
Your mileage can be a little squishy if you need to report more or less net income. For instance, if you did a shop on the way to the grocery store ... you can take the mileage to the shop and back if you need more deductions, or you can ignore the mileage completely and not deduct it because you were going there anyway. You can figure up the actual expenses for the vehicle use or take the standard mileage rate. If you use actual expenses, take only straight-line depreciation on the car, not any of the accelerated methods, to enable you to keep the option to use either standard mileage or actual expenses.
And if you have no idea what I just said ... get an experienced tax preparer to help you.
I know what you are trying to do. You are trying to increase the Earned Income Credit by showing more income. But one of the questions on the Earned income checklist is whether you *reported all your business expenses.*
in the specific example you gave, the IRS probably will count you virtuous if you consider the meal you got to be bartering income and take the whole $25 as income and don't deduct what you paid for the meal (because you benefited from it by not having to make hot dogs for dinner that night). If that is the case, I would report it separately as "bartering income;" deduct your paid-out up front, then add it back on a separate line as bartering income. That way you are treating all your paid outs the same, and then selectively adding back in the ones where you gained a benefit.
(You got $100 in fees plus $50 in reimbursements, $25 of which truly benefited you (keep in mind, you didn't benefit from your guest's meal), and was the reason you did the shop. Report $150 as gross receipts, deduct the $50 from that, to end up with gross income of $100. Then you deduct your mileage and other expenses from that figure. But add a line for "bartering income" and put $25 on that line. It will increase your net income from shopping, which is the final figure that helps you get the EIC.)
But you need to be consistent in how you handle these things. there are a lot of other things you get reimbursed for that are *not* of value to you. Example, I did a shop where I had to buy a membership at a flooring club store. I was reimbursed for the membership. But i was also told I didn't get to "keep" the membership, i.e., I couldn't use the membership to buy flooring with. So if you did a shop like that, it would be incorrect to count that reimbursed amount as "bartering income" because you don't benefit from it. There are reimbursement shops where you mail the item back to the client; obviously you didn't benefit from that.
And consider that you may "peak" the EIC and end up coming down the other side of it at some point. in that case, your motivation is to show less income, to stay at the "peak." Your odds of getting audited are slim. But if you game the system by maximizing your income when it benefits you, and then change how you report things when the benefit goes the other direction, you can be blocked from claiming the EIC for some number of years, maybe forever.
Which is why I suggest showing the bartering income on a separate line. That way your bookkeeping does not change regarding how you report your income and reimbursements -- you just decide you're not benefiting from all those fattening dinner shops, you're only taking a few bites, it wasn't worth $50 to you, but only the $5 it saved you by not eating at home, there are a lot of ways to approach this situation. But don't make this up after the fact. Decide why you're doing the shop before you do the shop, and do your bookkeeping accordingly.
And get someone to help you with this. Do not try to fill out your tax return based on what i said here. I do not know your full situation. Copy what I wrote here and email it to yourself, then take it to your tax preparer who knows your full tax situation and ask them if any of it can help you.
This probably has confused you mightily; but a qualified and experienced tax preparer will understand the concepts underlying my comments and will know what it means to you specifically.
Time to build a bigger bridge.