Hmm, well, with enough effort, you can wind up profiting by playing Cards (not sure about Slots) and tokens (which you buy with gold) to make tickets.
For example, I can spend 1,000g in tokens, earn about 1,000 tickets with those tokens in a game of Cards, and then sell those tickets in the Marketplace for 7,000g - 8,000g altogether. So it is very easy to profit by playing and earning tickets.
The problem is that this process takes time. Are you willing to invest this amount of time into a long-term goal of thousands upon thousands of tickets?
Let's say that you choose, instead, to buy this stuff off the Marketplace instead of working for it in the Casino. Simple. Just do some math to calculate the easiest path: buying the tickets vs. buying the items themselves.
The Spartan Helmet is the most expensive item (in terms of tickets) in your desired set. If you bought the item itself off the Marketplace, it would cost you approximately 170,000g. If you decided to buy the 300,000 tickets it costs to buy the helmet from the Prize & Joy, that would cost you, at the current rate for tickets, 2,700,000g.
I would recommend saving up to buy the items directly off the Marketplace. If you really want the several hundred thousand it takes to get them, it's not hard. Just set up a quest thread, play Booty Grab for 50,000g per day (close to an hour of Booty Grab), sell your tickets in the Marketplace in bundles of 1,000g and make some gold off of that, and you'll get the money in just a few weeks.
Hope this helps! Good luck!