I have a toysrus gift card. Can I buy toys equal to the amount on the gift card and return them to get cash?

NO....you would have to show them the original receipt. Generally store terms allow you to receive the same currency type that was used for the original purchase. If you paid cash you would get a cash refund, if you paid with a gift card...your refund would be a gift card. If you don't have a receipt stores now gift you a gift card instead of cash.
Here is their return policy....I found on the web
THE TOYS "R" US RETURN POLICY

--------------------------------------...

Toys"R"Us will gladly accept returns made within 90 days of the purchase date for most items. Items excluded from this policy are video games, accessories, and systems; computer software, VHS cassettes; DVDs; music; electronics; radio-control items; trading cards; collectibles and consumer electronics. See below for our return policy for the items listed above when accompanied by a receipt.

Please follow these easy steps when returning an item:

Be sure to bring your dated purchase receipt.
Receipts will help us process your return quickly and fairly. For your convenience, we also offer gift receipts. We will not accept any returns or exchanges without a receipt.

Please keep all packaging and accessories.
Please bring all original packaging, accessories, and instruction manuals that came with the item you are returning back to the store.

Please return items within the appropriate time period.
We will be happy to exchange items within 90 days from the date of purchase, or offer you a refund in the form of merchandise credit as long as the items are accompanied by a dated receipt.

We will accept returns of the following items within 45 days from the date of purchase: video games, accessories, and systems; computer software; VHS cassettes; DVDs; music; electronics; radio-control items; trading cards; collectibles and consumer electronics.

Return Guidelines for Video Games, Accessories, and Systems/Computer Software/VHS Cassettes/DVDs/Music/Electronics/Radio-C... Items/Trading Cards/Collectibles/ Consumer Electronics

We will accept returns of the following items within 45 days from the date of purchase: video games, accessories, and systems; computer software; VHS cassettes; DVDs; music; electronics; radio-control items; trading cards; collectibles and consumer electronics .The original, dated receipt is required for a refund or exchange, and the item must be returned in its unopened and factory-sealed package. If the item has been opened, it can only be exchanged for an identical item. Refunds and exchanges will not be given without a dated receipt.

If you have further questions about our return policy, please speak to a member of the management team in our stores, or call 1-800-869-7787. We will be happy to assist you.

HOW MUCH IS THE GIFT CARD FOR? MAYBE I WOULD BUY IT FROM YOU. LET ME KNOW.