If you have an art shop on FR you can copy your prices from there. I like 10g:1ms:10kp:10kt for simplicity, and in terms buying gems and moonstones with RLC(real life currency), that would be their values to each other, I think the current exchange rate is technically 14g/kt:14kp::1ms but you don't have to do that if you don't want to.
think in terms of RLC when considering your prices, even if you aren't accepting it, it helps you get a grasp what you're actually charging. I have it easy with USD so 1$ = 10ms & 10$ = 100ms, but depending on your currency you might have to figure out the exchange rate yourself.
Don't bite off more than you can chew, there are no consequences to not having pixel wolf game money, there are consequences to overworking yourself.
When in doubt price yourself higher, you can always lower it if it isn't working for you, but try not to underprice yourself, It's hard to figure out what that means when you haven't grasped your worth, and it's hard for other people to tell you what that is, in the end it's really up to your own discretion, but if you have a gut feeling you're doing too much work for what you're getting payed, raise your prices.
oh and take full upfront payment, don't do the half and half thing, you might think that it builds trust, but it doesn't, it's not worth it.