We had a 'minimum' spend in our office of £10. Highest was £20 max.
I spend about £18 and bought my secret Santa a Emma Bridgewater mug, her favourite chocolate and a fancy bubble bath she's well known to adore.
I got... A flimsy mug with cheap chocolates inside.
The previous year (a different office), I was given a pair of socks from Poundland and a small pack of M&M's, the spend limit there was £15.
AIBU to wonder how people can be so mean? 
DH is usually well known for this kind of cheeky fuckery, usually re-gifting a naff toiletry set from someone. However, last year he was bought a Peroni glass and beer which he loves so makes the effort now.