Wild Bird Sunflower Hearts

Had a bit of a shock earlier as I went to purchase a 12.5kg bag of Sunflower Hearts from B&M. Most of last year these were around £13.99. In December the same 12.5kg bag was £17.99 and today I had to pay £22.99.
Who knows what it will be when I need my next bag!

So.. is there a cheaper supplier that I can use for a similar size bag?

Thanks