CamaroBill122090

I have a 2000 camaro z28 ss and for som reasone about a month ago my car wouldn't shift in and out of second then went away this week the trans is acting up 1 and second are no longer functioning at all it grinds when u place it in gear and release the clutch and I start in third to move but I can put it in first and stop and as long as I hold the clutch it will stay in first no problem an second was the same about a month ago what's all the grinding and non functioning????? And what must I do?? I cannot afford a new trans and how much can you trust a used one ????