Does my cat have the flu or something else?

Alright on Oct. 20 this year i bought some cat food of Purina, the hairball and healthy weight formula, since my cats were getting a bit fat supposely. Then on the 22nd of Oct. one of my cat's got a cold started sneezing alot, he's stillplayfull but is still snezzing for a week now. Then my other cat got sick, she's not sneezing alot but it seems the mucous is in her nose but not coming out, and she sometimes wheeze's; well thats what it sounds like, she still loveable but hardly does anything like following me whereever i go around in the house or when i call her name Another thing i stopped giving them that food if that was the cause and gave them this Meow Mix indoor formula on Oct. 29. I cant take them to the vet due to money issues, im stressing trying to make them better plus i suffer from depression. Can someone pleasetell me whats wrong with them?