For the straight razor I would post a want to buy thread on the BST area. People on the forum are really nice and love to help a new guy out with a shave ready razor. (this is probably best option)

If you don't care what razor you get as long as its shave ready there is a guy on etsy that sells random (not best condition but shave ready) vintage razors for 40$ (or the kit that comes with a strop for 70$ which I would recommend). From what I have seen the guy is really cool and easy to work with.
etsy link https://www.etsy.com/listing/2539085...active_4&frs=1


If you want to choose your razor and think you will be able to take decent care of it Griffith shaving sells vintage razors for a good price and they will be shave ready as well.

Griffith link https://www.griffithshavinggoods.com...traight-razors