Every workamping job I've had that pays for hours worked since 2003 has taken something out (see below).
Some take out some hours to trade for your site and don't include that as income....some DO.
Almost every place has a different variation of how they pay/compensate !
I don't even think about any that want to report you as 1099 self employed because it usually is improper(see the IRS site for the definition of self employed) and they are trying to save money and paperwork at your expense....
You have to ask about their method carefully when you apply to know what to expect !!!
If you don't make enough to owe taxes (about $10,000) for a few years you can elect exempt on the W4 you fill out at the beginning of your new job and they won't take out fed or state(if there is any)taxes from your pay. Social security and medicare will still be taken out though.