Hi Andrea
Where are you exactly?
I wish I could help you but I don´t know for sure where you can find it. Here in Brazil and apparently in the USA, Chanca Piedra is very popular and you can buy it in every pharmacy.
I believe you should call pharmacies/chemists/drugstores and see if they carry Chanca Piedra in Tincture form. You may find it in shops which sell natural products as well.
If not, I can give you the website of the pharmacy where I get my tinctures here and you can try and order it, as a last resort. I pay about 3-4 US Dollars for a 250ml bottle of Chanca Piedra Tincture(really cheap!!)Freight should not be that high, I guess 10 US Dollars maybe???