I found a few options under $55 for Series 3 Martha while randomly looking through plus size women's catalogs. These are some of the best color/style alts I've seen in quite a while.:
Option 1 :
Woman Within Madison Scrunch bootie. $49-$54 depending on size/width Option 2:
Roaman's Claret Lace Up Bootie With Cuff. $39-$42 depending on size/width Option 3:
Roaman's Burgundy Daria Leather Lace Up Bootie. $49 Option 4:
Woman Within Darcy Lace Up Wide With Bootie in Claret. $39 These shoes would work well for River's TIA/DOTM outfit. They're a bit more expensive than the DSW alt posted a while ago, but I hope this helps someone.
Amazon- Report Alfonso leather boot in brown. $102 (not all sizes available)