Server giveaways often attract a lot of attention and can grow the server quickly. Some prizes could include gift cards, money, or free products from sponsored brands (can quickly bring in profit).
Prizes should be of interest to the winner, and therefor need to be non-gender specific, and appropriate for the player base ages (eg, nothing for under 18’s, etc). Prizes could be determined based on the servers current income. For example, if the server is making £100 weekly, a suitable prize could be over $50 if incomes are stable. Gift cards are a good prize as they are easy to give (just a simple code) and is easier than transferring large amount of money. If you sponsor a brand you could give away their products as prizes. This is a good idea because the brand is being sponsored to draw attention to it, and would therefor get more attention if it is given away in an event. Some good stores to make gift cards for could be Amazon, as it is a global store, accessible to almost all players, or virtual prizes, such as Discord Nitro, or Origin games. Virtual games could appeal more to the winner if they game a lot. A choice could be appropriate, between an Amazon voucher and a Origin/discord voucher of the same worth. Links: (most things linked are gaming supplies as it is a safe bet that a player might have interest in them).