My first DB was a cheapo 3/4 from China which cost me £300 pre-owned. I played it for about three months, realised that I was hooked, and bought a very decent (roughly a grand) Zeller 3/4 from @Clarky
The Chinese cheapo was, of course, nowhere near as nice as the Zeller, but it was perfectly playable and a cheap'n'easy introduction to DB. I can't remember how much I sold it for, but it's hard to imagine I took much of a hit.
This was all 15 years ago and prices will have moved on, but I suspect the DB rental route will always work out way pricier than simply buying a cheap bass.