How to get rid of and prevent razor burn?

I get really bad razor burn on my inner thighs and upper back of my thighs. I've tried shaving with moisturizing shaving cream and different soaps and without soap at all and nothing works. I've tried using special ointment but it didn't help at all. It sucks because I can't wear shorts even if its 98 degrees outside because my legs are either hairy or red and bumpy. I can't afford laser hair or waxing so i need some cheap solutions. Is there any thing out there that will help?|||Use a sharp razor every time. Keep it clean, sterilize it after every use with rubbing alcohol. Make sure you keep your skin clean and don't spread bacteria.