Bid limit and replenishment
Your available bids per month depend on your membership plan. Upon membership renewal, they are given periodically at a set interval according to the plan you have subscribed to.
Scroll down to the lower right side of your Dashboard to check your remaining bids and the time left before another bid is given to you. Once you reach your maximum bid limit, no more bids will be added to your account.
If you run out of bids, you can click the purchasing a Bid Pack* option from the Details tab of the project view page. This costs $1 for 5 bids. Bids bought will be added immediately to your account.
*Note that you cannot go over your max bid limit; buy only when you are low on bids.
Aside from that, you can also Upgrade to a higher membership plan to get a higher bid limit.