Can you still use the barcode scanner without Premium?

It's premium only now.

Up to you if it's worth the price. I've only ever used the free version since joining back in 2009. It does take a little more searching to find a usable, more-or-less-correct entry, and even then comparing it against an independent USDA search or whatnot. But with practice I can still find what I need in usually under a minute, and with one less bill to pay.

Premium only, but some countries are an exception as noted above. (I think it has to do with regulations about not removing features after a person has signed up, though. If that's so, you wouldn't get it in free MFP there if signing up now.)

I do have premium. I also never use the barcode scanner. People think it's going to be a direct pipeline to current, accurate information from the manufacturer. It isn't. Pretty much, what comes up is just what some user who first scanned the bar code input, and that can be out of date or inaccurate. Sometimes it brings up totally different foods, since some manufacturers reuse barcodes or other reasons.

There's always a learning curve with a new app. It only takes seconds to type in and look up items, and doing it that way gives multiple options in case the first one doesn't match the calories/nutrition on the package.

Personally, besides the accuracy issue, lots of my foods don't have bar codes (farmers market, bulk purchases, etc.). I don't always have the package in my hand when logging. (Fussing with my phone or computer while cooking is messy and fiddly.) It just doesn't work for me.

Unless you've used a scanner previously and know that's important for you, I'd suggest giving free MFP a try. Lots of people like the scanner and use it, yeah. To me, though, it's one of those features that sounds cool and time-saving, but turns out to be low/no value in the real-life flow of things. YMMV.

Best wishes!