The common rule is that if a company is located outside of Europe - like ss, adobe, etc. - no VAT is applicable if you live in Europe.
For tax purposes you declare the amounts payed by the agencies as net income. Keep an exact record of what is payed to you, no matter if you are a business or private person.
If an agency resides in Europe, then VAT is applied, but the ones I work for always give me a VAT included specification.