I am a newbie here and I am wondering.. Exactly how much does it cost to keep a website open?

Simsquirts was one of my favorite places for toddlers clothes and kid and nursery bedding. Most of the site was free. I only paid once for a download and it was labled a donation set. It cost me $5.00. I didn't think that was too outrageous because I periodically donate to the other sites I visit to help keep them afloat, and most of what I downloaded was free. Simsquirts closed after she brought her baby home from the hospital and didn't have time to make more donation items so her donations stopped and she couldn't afford the cost of keeping the site open according to the email I got from her..

Sooo...while I think it is outrageous to charge a subscriber upward of 5-10 dollars a month to subscribe (TSR comes to mind here and eclectic sims), to play the devil's advocate for a second, what is a reasonable request to help defray the cost of keeping a website open?