Bookshelves for sale. Very sturdy, bought a year ago, please see:

https://www.amazon.com/gp/product/B083WDWHG3/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&th=1

Tiered (See first picture, the shelf on the hardwood floor): $70
Non-Tiered (i.e. no gradient): $50

All 3 for $150.
Both of the non-tiered for $90

Pickup in Menlo Park, delivery possible for a fee.