I've personally have owned the MXR Bass DI (M80) and Tech21 Sansamp BDDI. Both pedals do distortion as a bonus but they both work great for DI. If you like the distortion sound, then the Sansamp BDDI would be the best option IMO. Either way, both can be found for around $100 used. I also really like the preamp portion of the Sansamp as it gives me way more control of treble and bass than my Ampeg amp does.
They aren't $40 like the Samson mentioned above, but they have more controls and offer however much distortion you want.
Agree, MXR M-80 works great for me.
