hi please can any body tell me how it hard to code to Upload and Download function using this API http://api.filesonic.com/l what budget should be for this ....
That depends on what it's being added to. Anything from a few hours to a week or two, depending on hoe complex the code surrounding the API calls is going to be, and how experienced the developer is. Figure on anywhere from $25-$100/hour, depending on how long you want it to take. (More experienced people get more per hour and take less time.)