Redeem 5x means you can redeem that particular offer a maximum of 5 times as long as all 5 items are on a single receipt. It's also fine to purchase just one, two, three, or four to redeem it once, twice, etc. But if the maximum is 5 and you purchase 6, you will only get rebate for 5.
On the contrary, it would NOT work for you to redeem it 5 times spread across multiple receipts (except in the case when the offer repopulates in your ibotta gallery).
It may also be helpful for you to know that often (but not always), after you've redeemed an offer, that very same offer will reappear (repopulate) in your ibotta gallery so you can do it all over again!
I hope this helps.