United MileagePlus Shopping is a popular online shopping portal. They have just launched a new promotion: from 6/21 to 6/30 (or as early as 6/19 if you have a Chase United co-branded card), if you make more than $250 in purchases through MileagePlus Shopping, you can earn an extra 1,000 miles. 
Details
From 6/21 through 6/30 at 23:59:59 Eastern Time (or starting 6/19 if you have a UA credit card; you should receive an email specifically noting the early access), make purchases through MileagePlus Shopping at participating merchants and reach a cumulative total of $250 to earn 1,000 bonus United MileagePlus miles. The bonus miles will be awarded in 8-10 weeks. The terms say that gift cards and cash equivalents are excluded, but historically UA has never enforced this and likely cannot enforce it. So purchases on eBay should be fine. If you spend exactly $250, that is effectively 5x miles through MileagePlus Shopping. If you have planned purchases, this is a pretty solid promotion. Are you planning to use it? Share your thoughts in the comments.