As of July 3, the iRobot Roomba Plus 405 is on sale for $399.99. This deal saves you $400 on list price, and is the lowest-ever price according to camelcamelcamel. Our robot vacuum expert has hand-picked this deal as one of the best ahead of Prime Day.

Amazon Prime Day typically brings great discounts on all sorts of electronics, but it’s a good idea to go for the expensive gear first. We consider robot vacuums to be in that category because, while there are solid affordable models available today,

Robot vacuums are incredibly useful, but tend to be expensive. Fortunately, I found some deep discounts leading up to Prime Day, coming up July 8-11 this year.