Birth Control Pills?

Does anyone know of birth control pills that are 20/100 (low-dose) that are covered by concession?
Microgynon I used to be on worked well however I went of it for a while, plus it was almost $20 a month! So I'm on femme-tab 20/100 now for $6.20 for a 4 month pack! However I'm feeling really gassy with body pain and belly aches feeling like throwing up, and migraines, so I think I should change to another brand, but as I don't work I need a brand that is covered by concession so it's cheap like femme-tab! Please help?!?!