The short answer is no.
If you don't have a greenhouse, you can simply use a sheltered spot in your garden so your seedlings are protected from the worst of the wind and rain. And a simple sheet of horticultural fleece tucked around them for the frostiest days and nights.
The second answers is....but why wouldn't you?
Here's the set up that I have and love.
Now, I bought mine during lockdown from Aldi, at the time of posting this video, they didn't have any available, but do always check with them as they were great value.
So, here are some links to similar products on Amazon:
Here's the link to a similar mini-greenhouse in the video:
And here is the slightly larger one - these have gone up in price a little since I bought mine and the shelving arrangements change depending on what you buy, but this one is an example of plenty of others you'll find on Amazon.
And if you want to get really fancy - here's an example of a plastic small polytunnel - this one is a little fancier than mine - hence the larger pric-etag, but again, different products are always popping up on Amazon so take a look: