My spouse and I are close to starting our own business under the Dutch American Friendship Treaty. I am going to come up with an approximate scenario of numbers. Can somebody please give me a ballpark idea of what I will pay the government at tax time? Assume that we gross 3500 euro a month from our business. This is just a straight transactions between myself and the client. I am married. But I have no dependants, No mortgage, No stocks or investments. No other income whatsoever. And no employees working for us. So at the end of the year we gross 42,000 euro. Based on what I just explained, can somebody please tell me approximately what we will have to pay the DUTCH GOVERNMENT at tax time? From what I gather, we will be having to pay the Dutch Government 50% of this. Meaning that we will be sending them 21,000 euro at tax time. Am I correct or wrong? And will we get any of that back? And if so ,how much? Any help is appreciated. Thanks.

IF you will START a BUSINESS ( proven by registering at the Kamer van Koophandel, Chamber of Commerce of your locality) and 42,000€ will be your only gross year income of both you and your spouse, you will benefit during the first year of business of a tax reduction as a STARTING ENTREPRENEUR. Ask your Financial Advisor/Accountant (you NEED one) to do that for you.
The Financial Advisor (who, of course, will cost you some money which, of course again, is deductible of your gross income) will also advise you on all sorts of deductible costs, like, for example, the room in which you work, your car, your mailings, your PC, all your purchases (keep your receits), your travel expenses (keep your tickets, even strippenkaarten) etc.
My educated guess is that your income before taxes will not be higher than 20,000€ maybe even less. With such an income, you would NOT have to pay 50% taxes! Isn't that good news?
Now, how much would you have to pay? I don't know, I'm not a "Tax Consultant".
BTW, you will need to have a separate VAT (BTW) bookkeeping as, at least in the beginning, the Dutch IRS will ask you to pay them the VAT every month.