For wood, i recomend homedepot, buy some pine rounded sticks i started with that and is cheap and soft.
But, want some good basswood on amazon:
https://www.amazon.com/Beginners-Premium-Basswood-Carving-Blocks/dp/B01MSYOWEY/ref=cm_cr_arp_d_product_top?ie=UTF8
​
I got those and are soft and very good.