If you're a low level and willing to be like afk most of the time, for exmaple, have school or something but have a labtop handy with Mabi downloaded on it or so. Go spam Sms such as Shadow Wizard Basic with people until you get an income of 30k. Then buy a farm, and seeds and then start off with a farm from 30k. That 30k becomes like 200~400k in a week if you tend your farm well enough. And you may as well do Holy Water Jobs at the Churches and Healer's House as well for about 10~12k a stack, depending on your server's prices, even around 15k people may buy as well. Do the Church Job of anywhere in Uladh and then warp with pre-cut wools to the Healer's House in Qilla, obtaining even more Holy water in around half an hour. If you're on Basic jobs, you'll get 8 Holy waters per 30 minutes or so. If you end up becoming Adv HW job, then you get like 20 HW which is two stacks, per half an hour. Either spam SMs, HW sell for a little, and then use that money on a farm. You can even go spam SMs and do HW jobs in Tailteann while you are tending to your farm, because each action takes a while to cool down before you can use again.
Unless you can stomach things such as Fiodh Int or so, get FB 10's or something, as long as you have a good defense set. The enemies drop some AR Pages as well, that you can profit out of. FB 10 expires, but you could sell it before it does. Get something like an Unrestricted Fiodh for 4, or get trustable people to come that you can repeatedly run and split the profits with. Since the things don't have much HP in the dungeon, you'll be fine as long as you can tank their extreme multi aggros like the Ship Rats in Rundal Advanced. The only thing that you'd probably have to worry about is the damage of the Giant Imps, or the Agros in the dungeon that spawn. They drop good stuff such as AR Pages that you can sell to people, and that becomes a good profit if you end up getting them continously.
Another good option is SM spam with people, but most likely the good drops that sell for a lot of money are in the higher leveled missions which probably you can't do until 1k. Since you are apparently total 500, you should be able to solo some things such as Their Method for Burgundy Bear, which would sell, but you'd probably need more dmagae if you have low max/min damage to WM the zombies. The zombies are just like TNN zombies, slow, but aggro a lot, and you should be fine as long as you got a decent WM to boot from on the mission. Or spam SMs that are cheap and fast and easy, and sell the crystals that you end up getting from them, such as the Arat Crystals and Life Drain crystals. Since people abuse G13 for the Golem and Life Drains, it may not be much of use though doing this, the only thing being of any use would be the Arat Crystals.
People also gachapon spam, but I don't really recommend this unless you're thinking you may be lucky. But mostly, this will make you come out disappointed, since you will use your money for it, and it may end up badly. Most people would have the worse luck with these, so I don't really recommend these unless you're extremely desperate and decide to give it a go, if you don't have anything else to spend it on.