Regarding the comments on cyanoacrylate, there is certainly a bit of technique to it and variations in the formulations. Loctite has a number of formulations that are designed to work in surfaces of different finish level as well as different types of substrates. If you've done it right then the bond is always stronger than any printed PLA or ABS substrate will be.
That said, you can get really far with your run of the mill $2 for 7 tubes CA with a little thought to the preparation and mechanical design. Par down surface imperfections with a blade, take advantage of tapering to gain closer su