Hello, I have done a similar thing for a Dogs Blogging website, they wanted a Dog calendar which people can put on their blogs. So we made the calendar and created the script which people could simply add on their sites.
To do such a thing, we will need a ASP.NET hosting with you. We will create the widget and host it on your site, the users will get a code for iFrame, which is like a small window which will open the widget on their sites.
To make it simple, we need to host the widget on your site, once its done i can help you with the code which users can use to add the widget on their sites.
Your design expectations are little higher as compared to the cost range, 10-30, and hence i have to raise the cost. Will you need a back-end to update the loan limits for the states yourself ? What will be the size of the widget, the one like you have on your site? If yes, then we will not be able to fit the US map in it properly.
Let me know your thoughts. Thanks