What size do you need? There's only going to be one foal born here early in the year, so I don't need all of mine. I'd happily loan you a couple and you could just mail them back after you're done.
Are you looking for the kensington quilted mini foal expandable blankets? They're the ones that come in pink or blue and say its a boy/girl, have an elasticy front. If so, chicks saddlery has them on sale for $10.49 right now
Pondlake Stables makes and sells very nice foal blankets of polar fleece with polar fleece leg straps to keep them on at a very reasonable price. click below on website to see samples!