These things are illegal.

Maybe not in your country, but they have been stolen from Eygpt, as it is illegal to export them.

These things are openly on sale at Amazon.com and EBay, just search for ushabti, and you'll find tens of them available in the auction at any one time for around $35 a shot.

Whilst it might seem rather cool to have this little figurine who is supposed to be your lackey, at the end of the day the purchasers of these ushabti are financing tomb raiding. Joshua at GarouMUSH said that

"It's like selling someone's grandma's wedding ring that you dug up out of her grave. Or, better yet, the rosary she was buried with because she had a deep spiritual connection with."
So if you buy one, you're a plunderer, a grave digger, and completely devoid of respect for the dead. I wonder if the curse of the pharoahs still holds?