SleepyCart is described as 'tracks prices on groups of Amazon products. This is super useful for international buyers, since combining many items together into a cart often saves on shipping' and is an website in the Online Services category. There are more than 10 alternatives to SleepyCart, not only websites but also apps for a variety of platforms, including Google Chrome, Android, iPhone and Windows. The best alternative is Keepa, which is free. Other great sites and apps similar to SleepyCart are Savelist (Free), Fetchee (Free), Price Snoop (Free) and PriceSpy (Free).
OneCart is an universal shoping cart. You can easily add any product from any online market to your cart and keep them in one place, you will always have-up-to date prices and possibility to find similar products in other markets.