With classics, you need to think about running costs / maintenance costs / parts cost probably more than purchase price.
For that money you get a Porsche (decentish 924 or an okayish 944)or you could get a Mini. I doubt I need to tell you the likely difference in running costs.
Apart from the example you gave, you’ve not said what you need to be able to do with said “classic” – if you need an estate car then I’d agree that an old Merc is the standout choice. If not, then maybe look at warm / hot hatches. Cheaper to look at less obvious brands, so Corollas, not Golfs etc..