Olimex AVR-JTAG-L JTAG DONGLE FOR PROGRAMMING AND EMULATION

AVR-JTAG-L is the best entry tool if you want to learn AVRs, it cost fraction of original Atmel JTAGICE but does the same. Note this is not AT-JTAGICE-MK2 and supports only ATmega16, ATmega32, ATMega323, ATmega162, ATmega169, ATmega128 microcontrollers. If you want to work with the newer devices with debug wire this JTAG will not do the job.