First of all, I'm proud of you for supporting the game with your money, that also helped set you off on a better start than I could do myself.

Now for some general ideas discussed in the past, check out this thread:
http://forums.spiralknights.com/en/node/4878

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My personal preference is the social networking side of things. I mentioned it in that topic but I'll do it here as well. You can have up to 250 friends and 100 guildmates, so make use of that.

How is that money? Saves time and energy. Surely you've noticed the first half of a tier is never really that profitable compared to the last half, so whenever possible, you should just skip those stages outright. With a large amount of friends and guildmates you can actually "pick" your stages. Your social tab will tell you which friend is exactly where in a depth so you can just join them whenever it suits you. If you are more patient than I am, you can even go up to the gate and look for a tiny person icon that matches where your friend is in a certain depth, that way you will not only know what depth they are in, but what stage. Perhaps you'd like to hop in on an arena, well that's one way to find one.

Asking before you do so is a kindness but it's not something you have to do (at least for me). If you really want in and they have a full party, you could also ask them to go solo in exchange for some energy/crowns.

Now another thing, I find pretty much all of Stratum 4 of Tier 2 is good for crowns, naturally JK feels the best but there's nothing wrong with the other ones so long as you are joining in past d13. And if you like selling mats, it would be good to run the other gates. If you have tier 3 access, this is even better, drop in on D23 or later and just do what you'd normally do. Kill stuff :D If you find a 5 star item, you just made gold if its a rarer one. I sold a sun silver for 9k today (that's cheap so I hear) along with two silverweaves for 14k together. I got both of those items on just one Stratum 6 run. Sure it was luck but hey that's a part of it :D But be aware, it's dangerous down there.

And this will help you out a lot if you are just trying to find those 5* recipes from Basil when you get the money. You can just ask a friend what's for sale at their basil (be prepared to answer friends if they ask you as well). Saving crowns is just as important as making money, and teleporting in on a friend is 'free" (energy cost). Tipping your friend a little bit is nice though but not required.

To help get you started with adding people, check out these threads, leave your info or just add everyone:
http://forums.spiralknights.com/en/node/4629 (general adding)
http://forums.spiralknights.com/en/node/7285 (JK specific)
I recommend adding people who seem competent on your runs as well. If you see them in a gate you run, that should mean they're active and likely to run a gate again. Removing someone stupid later is no harm :D

Oh one more thing, if and ONLY if, you find yourself being too lazy to turn your sealed swords/antiguas into their respective upgrades, then trade your jelly tokens for jelly equipment and sell it to Kozma. 3500 each for 15 tokens. This is ONLY if you don't want to level those items. Leveling those items would get you a much bigger profit but if you don't feel like investing the time, then that's another way of cashing in on them.

But all of this does require effort, honestly it might just be easier to spend another $20 to sell your CE again XD