Best to look on Ebay for a SAMS that is usually $12 or less shipped for used copy. Several vendors are constantly replenishing their stocks. Recently, the trend has been to drop the prices of the pre-40 channel units to prices around $7 or less unless it's a high demand manual. Same for 40 channel sets, very popular ones like for a 148gtl or 2000 will fetch more then $12.
Second option for Lafayette is Manualman's website. Pete carrys an enourmous amount of manual copies professionally reproduced at reasonable prices compared to many others. The difference here is he is a former Lafayettte owner/franchisee and has access to documentation that otherwise others would have.
If this set means much to you, it would be wise to pursue both a SAMS and original service manual even if you don't do your own service. I do restorations and this would be a major factor in me taking a job outside of the chassis I know and have docs for. SAM's while giving an annotdated schematics and alternate parts sources and an alignment procedure really offers little else such as theory of operation, circuit board xray views and other things that really assist a tech or anyone doing repair. A good combination is a copy of both to assist a tech or yourself.
While I don't reccomend this and it's best to find an Octal socket that was popular well into the 70'd particularly with American sets along with Jones plugs, you can cannibalize on old radio set using an old octal tube base. Worst case is you can use molex pins slightly spreade out with heat shrink tubing over them if this is a set you're going to keep and do the jump internally. That's a crapy way of doing it, but better then what's I've seen where people try to solder directly to the pins that presents a headache cleaning them up later if you do find a real connector. Octal sockets with a shroud should be easily found on Ebay or another cord for something else and rewired.