I love collecting ink blotters. To me, they look like miniature billboards. Still relatively easy to find...even the earlier ones since these were produced in such large quantities.
Most sell for around $20-$30. The early ones (1930s) are book-valued at $75-$150 but even those can be purchased from time to time for about $25. You just need to keep looking.
The last photo shows a miniature gold wood frame that a fellow collector actually makes by hand for ink blotters. I just wished I remembered who he was because these are real neat to display your ink blotters in.
I think I own about 20 different ones now.