Good question. I haven't answered it in a while and I bet my answer is a lot different than it used to be. IItems in ( ) over your price/availability criteria, but worth seeking because classic IMHO.
Speyside: Longmorn 15 Highland (other): Clynelish 14 ( 22yo Rare Malt @$120) Lowland: Auchentoshan 3 wood (21yo @ $120) Islay: Ardbeg 10 ('77 @ $79, Uigeadail @$89) Island (other): Highland Park 12yo or 18yo Cambeltown: Springbank 15
Campbeltown is tough right now. The old 15yo (tall bottle) would be my choice, but it's not available. The 21yo is available; classic but way over priced now. The recent bourbon Wood Expression, harkens back to Springbank's glory days, but probably not available now. Longrow 10 or (10/100 if in Europe) would be my current favorate that meets your criteria, but It's very peaty rather than the classic Campbeltown profile. So I listed the current 15yo, which is only so-so IMHO, by default.
Enjoy, John