What could you have done instead of drawing one of those? How much would that something else be worth to you? This is the opportunity cost and what you get out of doing something should be more than the opportunity cost because otherwise, you should be doing the something else instead.

It's reasonable to consider non-monetary benefits and costs on both sides. If you enjoy drawing commissions, you can weigh that as part of your benefit and reduce the fee you need to receive to balance things out.

A good place to start is to take your effective hourly wage (or minimum wage if unemployed) and multiply that by an estimate of the time it would take, plus any material costs.

For instance, my effective hourly wage is about 31 CAD/hr. I enjoy map making(my field of artistic endeavour), but working on commission takes some of the fun out of it, and adds some stress, so I call it even and leave it at 31 unless the project looks really appealing in some way. If I estimate that it will take 3 hours (the usual rule is to think how long it seems like it should take, and then double it to account for possible overruns), then I'd want 93 CAD.

Now, this would be what I'd want on a 'payment up front' basis. If there's a risk of not being payed, I need to raise the price to compensate, so that on average I get at least my opportunity cost back. If I estimate I have a 0.75 probability of being payed, then I need to divide by 0.75, which gives 124 CAD.

Conversely, if there's a possibility of royalties later, I can reduce the amount, though the math is more complex for this.

But all this gives a value in your local currency (Canadian Dollars in my case). If you want it in points you need to do a conversion. If you aren't using USD, convert to that (124 CAD = 125.53 USD right now)
Then multiply by 80 (125.53 USD = 10,043 ). Then decide how much you really want points. If you think they are as good as cash, leave it as is, but if you think it's less valuable, multiply by a number greater than 1. For what amounts to some store credit at dA, I'd want at least double the cash value. (20,085 )

This gives a minimum value. It may be that people will pay more than your opportunity cost in which case you get what economists call an 'economic profit'. Any price between your cost and the market price is reasonable. Above the market price and no one will buy, and bellow your opportunity cost would be irrational for you to accept. If the market price is bellow your opportunity cost, you should withdraw from the market, or maybe see if you can improve your efficiency (speed up, reduce material costs, improve your product to improve the market price for it)

As soon as you take any sort payment, or promise of payment, you incur some costs in stress, client expectations, long term expectations of low cost (raising your prices to something reasonable later may alienate people used to the low prices), etc. Free requests can avoid these costs, so it may be possible that taking free requests works for you, even when the market price is bellow the opportunity cost. You can pick and choose requests, don't have to worry about giving them their money's worth, and are less likely to loose people if you start charging a reasonable amount later. If you want 'commissions' for the simple sake of having them, rather than for money, this is probably the way to go.

Honestly I do not. Considering the fact that 80 = $1.00 I'd go as far as to say you are ripping yourself off. You are selling your artwork for less than a dollar each and in my opinion your art is worth much more than that.

I would say (and this is completely up for debate) that something like those would be worth around $5.00 real currency. Because 80 is worth $1.00 this means you should be selling these much closer to 400 each.

It makes me terribly sad to see hundreds of artists offering point commission for their artwork and setting themselves up to where their artwork is practically a steal. Again, this is my opinion and the actual cost of your commissions are up to you, I just thought you would like to know what you are selling them for.

Seems reasonable