If you are looking for a place to publish your work, check out lulu.com. It's free and if you sell your work they have good residuals/royalties.
My Work

http://www.tatepublishing.com/bookstore/book.php?w=1-5988616-1-1

If you already have a work at lulu.com or a similar site please share!

My suggestion is to look at all the options for publishing before using any indivisdual one.

Lulu seems to do good work, and they do it with an up-front attitude.  All you need to do is to fit into their formatting requirements.

If you are looking for exposure, keep in mind that "publishing" means printing and also publicizing your printed material with some kind of marketing strategy. US$4K seems really high, unless they are Really Worth It, which may or may not be the case.

I suggest that you look at Booksurge.com among other places for comparisons.  A quick check might be to Google all "POD Publishers" and compare services and prices.

I just had to sue a POD producer to get a refund when they were unable to perform as agreed. Caveat emptor!

dave

I've read that there are scam companies who make a living off of up front money. What if you send them the 4k, and they don't make an honest effort to sell your book?