You really need to do a lot more reading, and use the search function. MD players are okay, but most people are moving to at least budget compact flash recorders like the Microtrack 24/96. That and maybe some of Chris Church's mics and/or preamp, or the Sound Professionals mics, might vastly improve your recording setup, especially from a boombox.
Also check the yard sale section for used gear for sale. You can frequently find entire newbie rigs for sale, by people who are upgrading to better gear. Make sure you have some idea of what you are doing, and what you need, before you start spending your money.