Also bear in mind that not every baby like being swaddled! Our first baby loves to stretch out lol. We just used blankets when he was a newborn so there was no issue with sizing, then transitioned to normal sleep sacks once he could roll (as he would get a bit tangled).
With our first we initially had a blanket over him that was tucked in around the edges (check lullaby trust's guidelines on safe sleeping for how to do this) then when you feel like baby is big enough switch to a sleep sack. I would advise staying away from the ones with velcro swaddles as not every baby likes being swaddled. We used the tommee tippee sleep sacks because they're a bit more fitted at the top. We got all of ours second hand. Check Vinted, they have loads!
Buy small and if you have a little baby then you can use a cellular blanket to swaddle them 😊
Highly recommend love to dream but they do grow out them fast when little
I’ve been having the same problem! They aren’t the cheapest things to buy either so want them to get their use of it. We’ll either be swaddling with a blanket until our little one gets big enough to use the small size (as they need to be tight anyway) or I might by the newborn size from Vinted so I’m not wasting money if it doesn’t fit x