Any new comer to medium format, especially the TLR normally encounters some form of problems in one way of another. A limited amount of trial and error with some initial guidance from someone is therefore neccessary.
You need to know how to load the film, get used to the manual winding process after each shot, and also the unique way to remove the film cassette in the dark bag ( peeling away the double layer).
Getting a cheap medium format may not sounds like such a good idea particularly for item such as Lubitel or Seagull ( which I think fits your search) - which are prone to mechanical failure fortuitously.
The two entry level TLR are from the communist world ( centrally planned economy from factory of state owned enterprise with the key objectives of jobs creation to their people)
Its is built like a "tank" for the Seagull and is fully mechanical which has a high tendency of breaking down ( if buy as used) particularly the mechanical gadgets.
The lubitel are prone to light leakage problem and need experience to rectify them.
These are some of the issues to contend with. No doubt the lubitel has one of the sharpest Russian len and so is the Seagull.
It is my humble opinion for new comer to invest in a robust Seagull or if you more exploratory type, then I think Lubitel may possibly be a good choice because of the low price.