Small ac unit front coil freezes every time its switched on cool... furthermore bottom of front coil and back rusted severely.having drainage problems also... is ac worth fixing?will it be expensive to fix?

Assuming you are talking about a window unit (yes or no) it will cost more to fix than its worth. If you can get it to hold together long enough it probably needs to be taken apart and cleaned real good,the inside,the part you can`t see is what gets so dirty and causes the circulation to be very poor,and this causes the freezing up,, you can buy a good 8,000 BTU window unit for under $200.00

Yeah, I agree here. It will be cheaper to by a new window unit if that is the correct assumption... Can you post a brand and model for us so we know what we're dealing with? Thank you.