join some signature campaign , but 0.1 per week is hard i think
even if you have lots of legendary account you cant still be able to reach that amount in just a signature campaign only because 0.1 per week is too big enough but i guess that is possible in trading, gambling and investing , only if you have to risk a verry big amount. if you have a special skills in developing or coding and some indemand jobs these days for sure you can always achieve that amount in a single week without spending any amount as a capital. but overall the real secret to reach that amount is dedication , hardwork and willingliness to take any risk.
Of course with the signature campaign, 0,1btc per week is impossible, especially in this time, the price of Bitcoin has become higher, Bitcoin from the signature campaign is also lower to match the price of bitcoin. However, we also should not because the income is not high without participating in the field, this is a pretty good job, it is simple and there is not much risk as other jobs, gambling is the work should be put in the black list, it does not fit. Investment and trading is the most appropriate, but we need to have some reasonable capital and skills to achieve this goal, this goal is really quite difficult