Working in USA

Hi..I am Canadian...self employed and working in Canada...I plan on going to the US to work a few days of the month..then return...what type of working visa do i need?????

You need to state what you are doing in the USA for work. No one can answer you based on the information you are giving.

What I am going to be doing is going to county offices in each state and collecting overbid and tax sale lists...from tax sales...then finding out what money is owed to ex-home owners..find the owners...and collect money owed to them..and of course get a percentage of what I collect!
Most of the work will be done in Canada...but there will be times I have to go in person to get these lists.