How much Faab for Penny?

Penny hit the waivers today and I am wondering how much I should bid with my Faab. I, unfortunately, lost Mckinnon this year and I am just trying to beef up my RB core in hopes I have a solid 1, 2, and 3. I have a lot of possible breakouts but it is just a waiting game. My WR core is weak but there literally is no one available. My thought is to drop Sutton and pickup Penny but I have $100 budget and am wondering how much I should put down on him?

Current Team:
QB: Philip Rivers
WR: Adam Thielen
WR: Chris Hogan
RB: David Johnson
RB: Royce Freeman
TE: Reed
WR/RB/TE: Burkhead

Kerryon Johnson
Nick Chubb
James Conner
Emmanuel Sanders
Courtland Sutton

$30-$50 if you league is competitive on waivers…