Pregnancy advice

Okay so my husband and I have been trying to get pregnant for over 2 years , we've tried 4 different prenatals that are supposedly meant to help conceive , lubricant that is suppose to help conceive , pills from a doctor but I found out I was allergic so I couldn't finish them , we have sex every other day and still all the tests say negative , we can't afford the shots , or infertility .. besides birth control , What else can we do ?