We would not say this. I agree with Steven: it's acceptable grammatically, but it's conceptually rather odd. This is because 'plenty' is a wholly positive concept, so we can't make it negative. You could say 'I'll never have much money" or "I'll never have a lot of money" or "I'll never have a great deal of money" or "I'll never have enough money [to do something]", but not 'plenty'. Many students learn 'plenty of' alongside all the other quantifiers (much, many, a lot and so on) assume that it's a synonym and that it works the same way. In fact, that's not the case. 'Plenty' means 'more than enough', so it is not a concept that you can make negative.

It seems fine grammatically but it's a very uncommon way of saying it. Perhaps because of the negative form. 'I will have plenty of money if I don't go out on a spending spree on the weekend' and I will never have enough money if...' seem okay too. Just my two cents.

Su.Ki gave a great explanation. Grammatically, it’s OK, but it sounds quite odd. There are ways you can use plenty in a negative statement such as, “there are plenty of reasons why I will never date him again” but negating plenty doesn’t work.

Yes, that's fine.