Whereas individual games can be added to the cart, in bundles one is only presented with the checkout button. Thus one needs to purchase bundles individually, rather than having the ability to simply add them to the cart and purchase them all simultaneously. The latter would not only be more convenient, but would actually allow for the purchase of more games, as some cards only seem to be able to support a limited number of transactions with the same retailer in a short time period.

Two options. 1) Visit each bundle's game page and add the game individually to the cart, thus getting the full bundle discount or 2) Click the button with the price on the main page, which should add the full bundle to your cart. Will have to verify 2 in a moment, but from what I recall, it should work.

It works, but it won't add the games you already have.

Unless you own the full bundle.

Indeed.

Works for me. I've got 3 bundles sitting in my shopping cart all week. As they showed up, I added them to the cart and left them sit there to wait for the last day of the promo. Very simple, right from the home page or the more-bundles link, click directly on the "Buy now" green button present on every bundle. It puts the bundle in your shopping cart while you can continue shopping. When you're done, click the shopping cart icon and there is all the bundles and other games you put in the cart.

If you click directly on the image for the bundle instead, you're taken to the screen to pick and choose individual games, where you need to complete the transaction however. If you don't want all of the games in a bundle, simply add the whole bundle to your cart as described above, and when you're done shopping, visit the cart and remove the individual games you did not want. Keep in mind however that the bundles all have a big discount for buying all the games in the bundle and if you remove individual games then you'll usually end up paying a lot more because the discount drops from like 80% to maybe only 50% simply by not buying one game in the bundle, which causes the total price of the games you do want to possibly double in price or to go up significantly.

As such, it's almost always the most economical to buy the entire bundle, although there are exceptions such as only wanting 1-2 games out of a bundle that has 15 games or similar.

At any rate though, you can already add bundles to the cart and keep shopping without having to buy it immediately.