Thanks for considering the mixer I suggested, if you do look online for any, keep in mind, what I mentioned:
Its very useful to have the MB-20 meter bridge. If you look on Ebay, you will see Model 2, and 2A's, but not too many with the MB-20, which
usually adds to its price.
There were two versions of the 2A whereby one had faux wood side panels that look very nice and serve to tilt the MB-20 upward, which makes the 4 VU meters
easier to see. The other version has a bracket that attaches to the MB-20, which isnt tilted upward as much, though its still easy to see. Once you get used to the MB-20,
its a bit harder to adjust to say, a Tascam M-106, which only has two meters and are face-up- I have one, and find that I have to put a thick book underneath it to prop it up to see the meters at a better angle. Thats not to say the M-106 is not worthy, if you see a good deal on one, you might want to go for it, and even though its only 2 meters, its already part of the mixer, whereas with a 2A, you would need the additional MB-20, unless you dont mind working without one.
If you do get one, the hookup between the 3340, 2A and MB-20 is shown in the MB-20 op manual with a diagram, you just need some extra rca-rca cables to make the connections. The manual should be found online, but if you cant seem to find it, I can provide a copy or post the hookup diagram.
Some folks mentioned the concern of no xlr connectors or phantom power (which is also the same on M-106 by the way), so just curious what mic are you planning to use to record, is it a condensor mic?
You Can still consider something like an M-30 which came out in '82 (the Teac 2A/MB-20 was still being made, Teac vs Tascam overlap) It might look more complicated, but if you look and compare you will notice it borrowed ideas that originally go back to the 2A, 4 meters, 4 channel assign buttons (just added some colors to the pushbutton), etc.. The humble 2A is actually more ergonomic- note its upward slope, whereas the M-30 controls on the main area are at the same height as the meters- not thats it bad, its just an observation.
If you see an M-30 in well maintained condition and within your budget, you might choose that one as well and 'grow into it', but anyhow- a 2A/MB-20 can still get you going and allow you to enjoy your hobby, especially if you appreciate the vintage vibe it has.
Another very basic, low price mixer is a Tascam M-06, which can be found on Ebay, but I dont think its cut out for multitrack recording which a 2A can do with its output busses and channel assign switches. But you can still find the M-06 op manual online and its useful to read, as it shows diagrams to make it easier to visualize signal paths from the input thru the channels to the output.