Solo Friendly Cruiselines

I'm a single person - no family, no partner, friends who don't want to go on a cruise. I'm based in Sydney, Australia. I've looked at cruises as a single person and I understand why it costs more (making up for the loss of another person they could have had in that room), but it's not financially possible to cover the cost of two people on my own where I could afford it for the price of a single share.

Are there any cruise lines which are more solo traveller friendly, or things I can look into so I don't go into financial ruin to get on the sea for the first time?