Getting into MF is not just about increased resolution, but also about tonality, the fact that in most cases you are forced to slow down, the fact that you now can afford it, the love of using older camera, etc., etc.
To get started a TLR is the obvious choice, and you should be able to get something very reasonable for under $100 (Yashica, Minolta, Ricoh, Flexaret, Ikoflex, etc.). If you are prepared to spend a bit more, you could get started with a Mamiya C220. This will give you the option of additional lenses, from wide to moderate telephoto. You may or may not "click" with the WLF and reversed image.
Folders are another way, and open up more format options, from 6x4.5 up to 6x9. Contrary to what some seem to think, most folders don't come with bellows full of holes. Of the half dozen or so MF folders I have, not one has a single hole & all were bought off ebay. Some specific brands are known for holes due to the bellows material - Agfa for example - so for these be extra careful. For many other brands, such as Zeiss, the Russian Moskva and Iskras, Baldas etc. the bellows are generally OK providing they haven't been abused.
The best cost/value/quality compromise is in uncoupled RF folders, of which there are quite a few. The Zeiss Mess-Ikonta (6x6 version) with Novar lens is generally good value and very good performer, as is the Balda Baldix. For something less well known, and generally much cheaper, you could consider one of the later AGI Agifold cameras.
Cheaper but slightly less convenient, you could get a folder without RF and buy an accessory RF - these are generally pretty cheap. In that case, you will have a much broader choice, and at lower cost. You may like to grab one of the dual format 6x6/6x9 folders in that case.
Unless a Holga is really what you want, I wouldn't recommend one of these as a first foray in MF.