I went to Walmart yesterday to get chips/salsa for VBS snack room and found they had some really cute Dr.Scholl's slide sandals on sale for $9.88 !
They have a cushy rubber sole decent arch support and an adjustible buckle accross the top.I tend to wear a wide shoe so I adjusted it to the next to last hole and wore a pair most of the day today comfortablydespite being on my feet most of the day and having a sore right heel from a probable bone spur.(changed to some wedges for choir practice-dressier and had used a BDay giftcard to get the wedges and wanted to show them off to the friend who gave me the card).

I had my grandmother (whose in her 80's) try them on with the strap adjusted to the tightest hole (she's a 10 1/2-11 4a with a 5a heel) and they seemed to work for her too. The sandals come in a white based leopard,and a multi-color stripe,and yellow,hot pink,chambray-denim blue,and of course black.I got the striped ones,and the leopard,yellow and blue.I thought I'd share as they are extremely affordable and should be widely available.As the sole is rubber and the strap is sort of oilcloth/laminated cloth ,a pair of these would be nice for in a tote bag or car for rain (save the good leather/suedes).Hope this helps!