Except for a few HiFI brands, I doubt CD players are even made any more. Or even DVD players, those could serve just as well. You may find something on eBay perhaps.

Oops...see for example:

https://www.amazon.com/Portable-Rechargeable-Headphone-Anti-Skip-Anti-Shock/dp/B07ZJ96CD8/ref=sr_1_1_sspa?crid=2QXNNRR23JQ8J&dchild=1&keywords=cd+player+portable&qid=1621820112&sprefix=CD+player%2Caps%2C403&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExMUI0STY0WkRQUzhDJmVuY3J5cHRlZElkPUEwMDU1MDcyMkVVWU1VWDVSTzFTViZlbmNyeXB0ZWRBZElkPUEwMjQ4NzY0N1FIMEpEMzJBVVVaJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

I've seen these and yes, they are affordable. An additional question would be does this type of CD player line out into the line in port of the Five?

If it has a headphone jack, yes.

Personally, I wouldn’t use a headphone jack, as that comes after an internal amp - which may not be great on a portable.

Something with a line out would be my preference - maybe something like this :-

https://www.amazon.com/Sony-DVPSR210P-DVD-Player/dp/B007F9XHBI/ref=sxin_9_ac_d_mf_rf?ac_md=3-2-RW5lcmd5IFN0YXI%3D-ac_d_rf&cv_ct_cx=dvd+player&dchild=1&keywords=dvd+player&pd_rd_i=B007F9XHBI&pd_rd_r=badc61f5-72c6-42a5-93e4-03b1410564e3&pd_rd_w=TEaOo&pd_rd_wg=BcdHQ&pf_rd_p=89fa575a-c44e-401e-be03-82c92ec5e029&pf_rd_r=18RM0MJ14X11F46CV80S&psc=1&qid=1621854994&sr=1-3-89f8c401-73d8-4caf-b340-e9b34f2a8bae

A Blu-Ray or DVD player can play CD’s, can be bought cheap and most have line out. You may even have one in the house.