A row has broken out over a Highland Council-run school litter scheme which offers pupils the chance to win £10 Amazon vouchers.
MSP John Finnie said prizes should have been bought from local businesses, and not a company criticised for how much tax it pays on its profits.
Highland Council's leader Drew Hendry said he was disappointed an innovative scheme was being attacked.
The trial project was awarded £24,000 by Zero Waste Scotland.
Ten secondary schools are involved in the effort to reduce litter and recycle more waste.
Pupils taking part are entered into a prize draw to win £10 Amazon vouchers.
Mr Finnie said the scheme should have been an opportunity to involve local businesses.
He said: "I would have thought it much better if this is the style of scheme that the Highland Council is going to enact with public money from Zero Waste Scotland, that it should have money that was directed towards local shops."
Mr Hendry said only a "tiny amount" of the funding was being spent on the vouchers.
He said there were plans to look at involving local businesses at a later stage.