Anything that keeps people up to date on whatever they need. News or whatever. I just saw a newpaper offering an ipad subscription service that was .99 cents a week and it was really popular. I'd go along something for the mobile community along those lines and try to give them something really useful...or many things. Give the MOST value you can for a dollar and ask yourself "Would I pay $1 a month for this? Is it worth it? Is it something I want or something I need?" Hope this gives you some ideas.
This is an interesting topic.. what type of website do you plan on making? I don't think there's anything I would pay $1/month for that I wouldn't pay $10/month for. It's the same amount of work to pull out a cc and pay. If it's worth buying, it's worth buying. But that's just my opinion.
Totally depends on what it is. And if it was $1 a month I would want the option to pay for the whole year. OR make it $2 a month or $12 a year or what ever value you come up with. 99cents seems the go these days with iTunes and all that ($1.19 in Australia for some reason even with our dollar been strong)
I wouldn't pay $1 for anything - price just seems too low to deliver any value. But I would, and do, pay more. I pay $4 for an ezine, I pay $19.95 for voicemail quotes on my phone each month, and I pay substantially for coaching every month.
Web Hosting gets a lot of subscriptions, if sold at $1/month Do share what you are planning to do with $1/month subscription