Im renting a plane and im taking a passenger with me. If I dont have a commercial can they pay my rental?

With a single passenger, you can share up to 50% of the cost, no more. Even if you had a commercial pilot certificate you could not charge more unless it was your own aircraft and you had a Part 135 air taxi certificate. Be sure you have renters insurance. It's a very wise investment.

Technically no, you're supposed to share the cost equally. (If you have 2 or 3 passengers, you can all split the cost into 3rds or 4ths).

But that doesn't mean private pilots don't have their passengers pay for the rental in full. Many pilots have their passengers give the rental money in advance. How's the FAA going to know? And I also know of several private pilots who are actually paid to fly people. It's not technically legal, but again, what the FAA doesn't know, won't hurt them.

They cannot pay your whole rental according to FAR 61.113, limitations of a private Pilot In Command. This is not to say however that they cannot pay at all. According to the same regulation, you must pay a proportional rate of the flight. One passenger, you each pay half, two passengers, you all pay thirds and so on. This is not to say that you cannot be paid in full, it just can't be for the flight. If your flight runs you $120, pay your half at the airport and have them pay theirs, then go outside and pick them a beautiful dandelion and use your skills of persuasion to sell it to them for $60 cash on the spot.

No, the passenger cannot pay the rent. You can share pro-rated costs with him, but he cannot pay any part of your share. The FAA is very touchy about non-commercial pilots being paid for almost anything beyond part of certain expenses of operation, so beware.

Not legally for the entire rental but you can cost share on an equal basis.

Some of it.

Make sure to charge them for your other services.

loopholes are everywhere