Yes. If the bonus is 100% free, then you have nothing to lose. If the bonus requires a deposit and comes with wagering costs, it is only of value, should the wagering costs be lower than the profit you make. An example of this would be that the wagering total is €50, but you win €5,000, then it makes sense to pay €50 for the larger return. Beyond these factors, then a bonus would have no value to it. You are not obligated to see out an offer. If you win €10 and the wagering is €300, it makes no logical sense to pay this higher wagering cost.