Older Lada (2101, no Niva/Samara) to about 2t€ – where to buy?

Hello, my son (18J) would like to buy an older Lada, preferably from the model series 2101 from the 70/80 (no Niva/Samara etc.). He wants to spend as little as possible, up to max. 2000€. The car should be ready to drive and will be registered (as a normal vehicle, no old/youngitmer). His friend owns a car workshop where repairs (if necessary) could be carried out cheaply. Without a discussion about his motivation, about the insurance (we have in the family) I, as a father, would like to help him. At mobile.de or similar you can find some copies, now I get a bit of stomach pain, if I read “papers no longer available”, “door lock just renewed”, “condition very good, now some repairs have to be ambushed” etc. Are there e.g. reliable dealers specializing in such cars? Or forums? Thanks in advance! Best regards kappa13