A lot of the Listers I know about have a lot more $ into them than that but you never know what folks may want to sell them for. I already got a couple responses back but both were indicating something like $75K. A lot depends on what was done to the car but back when they were new from Beck/Avanti they were generally $25-30K without enginer/trans and a number of other bits and pieces. It may be possible to get one that has not been completed as well, one of the guys has a friend who has 2 of the last Beck/Avanti cars and I am not sure either is finished. Anyway I will forward what I get back, although I requested that they contact you so I don't have to play middleman.
Welcome. I started this Lister page on VRL but have had mixed results. Alot of the Lister folks I know prefer email so we keep an active email distribution list as well. I will send out an email to them and see if any of them plan on selling or know somebody who is selling a Beck Lister. A few months back one of the guys in AZ was considering it but I am not sure if he changed his mind or not. Also I have seen a red Beck Lister for sale in NY posted on the web off and on over the last year or two but unfortunately I do not have the guy's name. You may want to do some web searches and see if it still shows up.
If you want a Lister but not necessarily an old Beck Lister you could also contact Lucra who now owns the rights for it and manufactures the car now know as the LC470. They have made some significant improvements but are quite a bit more than the Beck car sold for.