It's a bit of a conundrum to me.
Entry level means "on a budget"?
A car with previous rust problems that has been tackled well (bare metal shell, new front strut structure, likely fenders and sills etc) will be starting around 50K. Likely partially finished, no upgrades etc.
For less, you might find a survivor car that does not exhibit rust poking through...yet.
It's a gamble.
Here is a reference; 40K brought rust bubbles in the rear quarter panel. You'll drive it, smiles aplenty, and enjoy it likely for 10+ years without it falling apart. But it'll keep deteriorating.
To fix the "bubbles", it is not just the skin that needs fixing, as it goes down into 4 layers of steel likely, and they include sill structure and rear wheel arch. Pretty tough corners for a professional metal fab shop.
Thread '74 3.0CS on BAT'
https://e9coupe.com/forum/threads/74-3-0cs-on-bat.48623/
My car was much worse, I still enjoyed it immensely. Firstly driving, and then the following 12 years of resto... and counting.