There is not a bigger lot of  TI-99 4a, computer hardware and software on e-bay. 

4- TI-99 4a computers

1 -  TI expansion box

1- 5 1/4 inch floppy disk drive

1 - Disk controller card

1- 32 K x 8 memory expansion card

1- RS232 interface card

1- flex cable interface card

1- phone modem

1- set speakers

2- cassette players

1- speech synthesizer

2- sets of joy sticks

3- video modulators

15- cassettes, various games, software programs

29-  TI games, programs,  cartridges,  some rare

8- 5 1/4 disks.

Cords, cables, adapters, information, books, instructions, etc.

See pictures as a description

All electronic devices in working condition.