I saw the following deal the other day, which seems nice. From KosherKouponz, a set of Onkelos on the Torah: Understanding the Bible Text, for only $130, where the regular price is $200.
They are also offering a similar deal at Amazon, but not as good a deal.
But if you look at the website for the YU Seforim sale, they have an even better deal:
Onkelos - Bamidbar(Numbers) $23.60 In Stock Add to Cart
Onkelos - Beraishit $23.60 In Stock Add to Cart
Onkelos - Devarim $23.60 In Stock Add to Cart
Onkelos - Shemot $23.60 In Stock Add to Cart
Onkelos - Vayikra $23.60 In Stock Add to Cart
Onkelos on the Torah 5 volume set $118.00 In Stock Add to Cart
To give you a sense of what this work on Onkelos is like, I'll provide this image. Follow the third link above in Amazon to get to Look Inside:
The pages alternate, and thus they also providing the Biblical Hebrew text of the Torah with Rashi (not shown). What is pictured above is a vocalized Onkelos, a facing English translation with interesting words or phrases bolded, and a running commentary below explaining what makes those words or phrases so interesting.