Probably oleander aphid, common to milkweeds (of which butterfly weed is one).

Damn, is this a disaster? Should I return them and complain?

It's not a disaster. The aphids should wash off with a good stream of water or you could use insecticidal soap. However, I would not be pleased if I brought a plant home with this affliction, sale rack or not!

Looks like spider mite damage, too. Matt, plants are put on the sale rack for a reason.....it won't sell for full retail. Personally, I dislike those sale racks as a lot of people end up with problems that they don't know how to handle.

It's up to you to inspect a plant very carefully before purchasing it. I'd be sort of surprised if they refunded you the price of a plant on discount. The usual policy of the big box stores is to dump infested and infected plants

Oleander aphids are extremely common on milkweed. But because the plants are a primary food source of the Monarch Butterfly caterpillar, it's not recommended that you use anything but plain water and squishing to get rid of the little pests.

Thanks everyone for all the help, I got most of them washed off. I don't really mind them eating, but afraid of them destroying other plants. Maybe next year I'll buy some ladybugs

This particular species of aphid is only found on milkweed, oleander, and a very few close relatives.

Best idea is to let ladybugs find it naturally, which they will do happily, if your environment is inviting.

They always find my milkweed here, but really do not seem to cause any lasting harm - in fact, they serve to attract ladybugs, lacewings & hoverflies & their larvae.

My butterfly weed has larger orange bugs/beetles on it. I just noticed them today, all over the pods. I haven't had a chance to look them up yet- does anybody have any ideas on what they are or if I should spray them off?

Jess, They're probably milkweed bugs and milkweed beetles. Technical terms.

Comedy, I've been noticing those larger orange & black guys around my yard lately too but had no idea they were munching on my butterfly weed.

i get this stuff to help out the (allegedly) threatened monarch and all I get is these bugs! That's super.

I have quite a few milkweeds of different types in my garden, all of which can be visited by the yellow aphids. But as someone noted, they don't do much harm and disappear fairly quickly. I occasionally spray them off with water if I get around to it, but never use toxic chemicals