Any tax experts here?

[Colon™]

Do without. At the end of the year, file a tax return. If you did not make too much money, you will get it back. If you do owe taxes, you can deduct that from your Belgian income.

Do without what? I suspect I can't file a tax return without an ITIN.

[Colon™]

If you make money in/through the US, the U.S. taxes you. Belgium has agreed to not tax you in that income. File a US tax return. If you made less than $15000 USD or so, you should get it all refunded.

Can I file a tax return without an ITIN or some other costly or time-consuming process though?

[pchang]

Do without what? I suspect I can't file a tax return without an ITIN.

Make do with less money. If they withhold the money, they have created a tax ID for you. Use that to file your tax return.

[Colon™]

Thanks for the help pchang, but I will be needing an ITIN for that.

http://www.irs.gov/Individuals/International-Taxpayers/Taxpayer-Identification-Numbers-%28TIN%29

[Aeson]

No, it's about selling prints through an American site. The buyer payes the site, the site pays me and witholds 30% for Uncle Sam. I'm trying to learn whether 1) that income will still subject to Belgian income tax afterwards, 2) since The Belgian govt would probably subject me to a lower tax rate, I can reclaim those taxes, or alternatively, I can just not pay Uncle Sam's 30%.

The picture I'm getting is this: as a matter of principle (per tax treaty), it should be my govt that has the right to tax me on that income, but Uncle Sam doesn't care. Also per treaty the Belgian can't tax me on that income again. I can probably avoid the withholding tax by filing an ITIN but that's supposed to take a long time and be expensive, thus not worth the bother. After all, why make it easy for foreigners not to pay a tax they're not supposed to be paying?

So it's royalties and you are a non-resident alien without activities in the US:

http://www.irs.gov/taxtopics/tc851.html

You should be able to set things up so that there is no US withholding, if the site you're selling through allows it. Here's Google Adsense's policy on such payments and a description of what constitutes US activities for instance:

Why can't I submit a W8-BEN form as an individual?
Based on our understanding, due to the nature of the services provided by the Google AdSense program we cannot accept a W-8BEN form from an Individual.

If you are a nonresident alien individual who earns revenue through our AdSense program, this revenue is characterized as payments for personal services. Therefore, as stated in the instructions to the Form W-8BEN, you must complete the Form 8233 rather than the Form W-8BEN if you believe that you are entitled to an exemption from U.S. income tax withholding on AdSense payments by Google.

However, before you resubmit a Form W-8 or a Form 8233 we recommend that you review the description of US Activities below to confirm that you do have US Activities and are submitting the correct IRS form. If you do not have US Activities, you will not need to submit any tax forms.

United States (US) Activities involve having employees or owning equipment in the US that are involved in any way with revenue earned through the AdSense program. This includes, but is not limited to, owning a web server or owning a hosting service in the US, or having employees in the US who are involved in either:

setting up a web server, hosting service, or website
developing content for your website
marketing to create a user base for your site
telephone support for your site
buying products for your site
maintaining your site
Generally, utilizing an unrelated third-party US web hosting service to host your webpages, renting web servers that are located in the US from an unrelated third party, or having your payment sent to a US Post Office Box or mail forwarding address, do not of themselves constitute US Activities.

If you do not have US Activities, please click on the Foreign Publisher with no US Activities link and agree to the statement on that page. In this case, no tax forms are required.

If you do have US Activities, please follow the instructions on the Tax information page to update your current form, or to submit a new form.

Please note that the tax information collection interface and any tax-related information provided by Google is not intended as and should not be construed as legal, tax, or investment advice. You should always consult your tax advisor to help answer specific questions regarding how tax laws apply to you and/or your business. The tax summary we have provided is necessarily incomplete, and the tax laws and regulations are subject to change. Therefore, Google does not guarantee and is not liable for the accuracy or completeness of any tax information provided, or any results or outcome as a result of the use of this information.

[Sava]

you should grow weeed, sell it, and not pay any taxces