It's dicey at best. I wanted an online deal for a cheap foam mattress I wasn't going to take home with me from my daughter's house- about $199 if I remember. An BNPL offered $13 a month. I figured I would put it on autopay and forget about it.

Of course it turned out to be a Synchrony product, which if you don't pay on time can immediately jump to a 27-33% range.

My purpose was to add a low percentage of use credit card to my two credit union credit cards, thereby lowering my overall credit usage by averaging the $4000 limit, of which $200 was 5% of card usage to my others. I wanted to bring the average % of usage down to up my credit score.

Which it did. But of course things went wrong right away. Synchrony took $26 a month, instead of the promised $13. Not a financial disaster but scammy as hell. They said that $26 was the minimum they could accept. Patently bullshit and classic bait-and-switch. I cut up the card the second it came in the mail- never intended to use it for anything else anyway.

But it was a pain and scam and after two months of trying to make them live up to their offer I paid it off.

I still have a Synchrony product- Chase sold a chunk of their outside credit product to Barclays, and the 18% card (which I kept at basically zero) jumped to 22%, now 27% as that is also a Synchrony product.

PayPal credit also sold out to Synchrony with the same outrageous rates. It used to be handy with a 12 month zero interest deal and I used it for plane fare. But once they sold to Synchrony it was a big no. I have credit to use there but I don't.

I stick to my credit union cards and a line of credit.

I need the ability to use credit since my daughter in Texas is waiting on a liver. Before she got sick I used it to go to Mexico for teeth implants-- the whole reason I built my credit in the first place.

For my relatively low income I have excellent credit and a real credit usage just under 50%. Of available credit to me, I'm way under. My goal is to get the two down to 33% and have lots of room for emergencies.

Bottom line, if you want to build credit go to your credit union. Then if your engine blows up or you have a family emergency you will have credit that's the lowest rate possible for you. Which is right around 12-13% right now.

BNPL is a useful tool but dangerous if you are struggling.