The Commodore 64, Atari 800XL, and Apple IIc (because of it's built-in drive) are probably good choices for retro hardware from the 8-bit era.
If you want to have the full retro computing experience then you'll be messing around with tape and disk drives and probably will also need to be ready for doing some repairs because even untested computers are still selling on eBay for up to a couple hundred dollars, even without all the peripherals. Tested ones even more. You can also try Craigslist or some of the retro computing websites such as
www.Amibay.com or
https://www.lemon64.com. Then you'll also need game disks and tapes. However if you are lucky enough to score a working retro computer there are new solid state devices that emulate disk drives and can be attached the same way the old drives were. Those devices use a USB or flash drive to hold the games, who's images you can download from many places and transfer onto the flash drive using a modern computer.
If you don't want to mess around with old hardware the new 'C64', while using a custom emulator under the hood, has much the same feel as the original Commodore computer with a nice clicky keyboard and a decent selection of games installed. You can add other game images using USB and the C64 even has the original Commodore Basic as a boot option so you can type in your own programs and save them to the USB 'disk'. It can't use any of the original Commodore 64's peripherals however and can only output HDMI so you would need a downscaling converter to play it on a CRT TV to get the full retro effect.