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I hope it will be there, when I manage to buy it

So I went to Blala market, and I saw a nice blue Ford, and I hope that it won't be already sold, when I manage to afford its price after few months from now.

I feel that I can't say "when I'll manage to". But I need someone to explain it to me.

2) Also I don't know when I should put comma before "when". I guess it is related to whether the first clause can be understood without the second one. Correct?