I currently own the base game on steam but I really want to get all the DLCs.  Unfortunately I also have to feed myself and do not currently have 90 dollars.  I am wondering when the next steam sale will be for endless legend DLCs.

The game and its DLCs are on sale quite often, with no longer than three months in between sales over the last three years. The last sale was two months ago, so I think it’s not unreasonable to assume that there will be another sale within a month or so. Certainly at the latest at the Steam Summer Sale around the end of June.