I found this a few days ago. Got a bunch of codes and thought i would share some. Also the link to get your own. This is only for new accounts. Codes can not all be redeemed on one account. Credit is only good for 2 weeks after the code is sent. Go HERE to get your own.
You can use fake info. They send the codes anyways. My first bunch i got took 2 business days. The second set only took 1 day. So it varies i guess. I only tried entropay VCC and it did not work. Feel free to share your findings with what vcc would work.
Edit:
After you have redeemed the code you have a year to use the promotion. You have 2 weeks to redeem it.
link: http://sh.st/2OmuN
Terms and Conditions:
Promotional credits expire upon the second week after the date this email was originally sent. You are responsible for all charges in excess of the promotional credit. (Control how much you spend by setting a daily budget and ending date for your campaign. You can turn off your ads and campaigns at any time. However, your ads may continue to display for a short period after the applicable budget is reached. As a result, you will be charged at the agreed upon rate up to 20% in excess of your budget.)
This promotional offer is only valid for new LinkedIn Text Ads or Sponsored Content customers using Campaign Manager through the LinkedIn website. One promotional offer per LinkedIn member. This promotional offer can only be used once, and may be forwarded to another LinkedIn member, but cannot be sold or bartered. Void where prohibited or restricted by law. This offer may be revoked at any time for any reason by LinkedIn prior to your creation of an ads account and entry of the promotional code.
Promotional credit will be applied during the creation of a new ads account when you enter your billing information in Campaign Manager. Promotional credit cannot be combined with other offers or discounts or applied to previous transactions. The promotional credit cannot be redeemed for its cash equivalent or any other services on LinkedIn and will not be replaced if lost or stolen. Promotional credit will not be applied towards taxes, currency conversion fees or other charges imposed by third parties. Once applied, the promotional credit is not transferable. No cash or credit back. All ads are subject to the LinkedIn Ads Agreement and the LinkedIn User Agreement.