I used to work for Venture, they are cunts to work for me, and im now back with the photographer i used to work for and the prices are high yes, but the cheapest thing we sell is a 5x7 framed pic for £70.
That might sound a lot, but for that you get a 1 hour session with the photographer, who takes around 200 shots, photographer then edits the pics, takes out all the ones she isnt happy with etc. Then they will do some light airbrushing, get rid of blemishes, stray hairs, swap heads from other pics if needed, lighten the background, stuff like that.
All of that takes time, then they make the slide show of your images for you to come back and view, so your one hour session, one hour viewing and couple of hours at the computer tidying up the pictures all adds up to a lot of studio time and money. You arent under any obligation to buy anything, and if you have no intention of spending anything the best thing is to say so at the start of the viewing, its appreciated.
Like i said, Venture are shit to work for, but they are a business and are in it for profit, but nobody holds a gun at your head, just be honest with them, tell them you cant afford to spend anything and wont be taking out finance either, simple.