The Luxe Life at Zappos
Let's do a quick search, shall we? Criteria: women's shoes, size 8, medium width, any heel height, any price, black. The results? More than 530 styles that range from a high of $1,114 for Cesare Paciotti t-strap pump made of haircalf and accented with a crystal vamp ornament to a low of $79 for an adidas by Stella McCartney slide with a rubber sole.
A quick search on boys' sandals (no criteria) brought up 13 styles that range from a $224 Armani Junior sandal with straps for infants (!) and toddlers to a low of $56 for a D&G Junior slide for toddlers.
You can browse by designer, too, that is, if you haven't fainted from sticker shock or spent your whole month's apparel budget on sandals for your children.