I'm originally from Germany and I'm in Jacksonville, Illionois for two weeks.
I don't know whether it's teh right category I started the topic in, but I think it fits best.

Now I'm looking for Low Pressure Sodium Lamps, but I don't know where I could get one of them.

Does anybody know where I could find one or two of them?

Thanks

Try a shop that sells surplus lighting, or a lighting wholesaler...they may have some old stock, otherwise can't say. Good luck!

Another option if you can't find any locally is to order some online, ship it to where you are staying and then grab them when you are there.