I think which issue it is is important with these, because the UK ones have the puffy stickers that the American ones don't and they are also harder to find.
I'm trying to remember what I paid for the ones I have.
Lily was £35 (UK box) but she had been taken out so not sealed. She is mint and complete, though, and her stuff hasn't been disturbed. The current exchange rate is insane but I think in old terms when I bought her that would've been around $60?
Tropical Breeze (French box) was maybe $120 or $150? She was a grail for me, though, so I was willing to pay a little extra to have the right box design, even if the language was wrong!
Rosedust I got from a carboot sale I think for about £3...she's also been out of her box before, though...and I had to get her sticker separately.
Morning Glory (US box) cost me £50? So $80? I dunno, US boxed ones seem more common...especially first set. Not so much second set, they seem more hard to find in both box styles.
So I guess around $100 is about right for a sealed first year flutter in a good box - though having stickers may jump up the price.