And some of the Chinese manufacturers like Boaer and Jin Hao has been turning out solidly build fountain pens at a fraction of the price of western prestige brands.
Also, a plug for Wingsung! They'll look very similar to twsbi or parker 51 at times, but imo they've added some little touches that improve on the twsbi.
Yes, definitely! I just bought a few Wingsung 3008s from eBay (a few dollars each, I think) and they're super-smooth. Couldn't believe I got a TWSBI-like piston filler for that cheap. Only downside to the cheap eBay pens is the shipping time...
You'll find these on ebay or etsy a lot. Aliexpress too. I would recommend also Wingsung 601 (for the parker 51 vacumatic experience), the Wingsung 698 with a gold nib for a nice piston, Hero 100 for an aerometric parker 51... or if you want more modern designs, look for Moonman, Penbbs, Live In You brands.