I think it costs more because you're not paying for as much up front. It's the same as paying for a monthly gym membership as opposed to a three year membership. The more you pay up front, the cheaper the overall deal. In this case, you can pay every three months, every year, or every two years (the cost goes down as the length of membership increases). If you only want to hang out for three months, paying 12 dollars might be all you want to do.

This same pay mechanic can also be seen with magazines. Purchasing one, versus purchasing a subscription for a year or two years. I think instructables is just sticking to the same pay mechanic that's been around for decades.

I think the OP has a valid argument. If the price is suppose to be cheaper when paying for a longer membership in advance, then the quarterly option doesn't make any sense.

Right now a monthly membership is $1.99 per month. A 2-year membership works out to $1.66 per month, but a quarterly payment is $3.99 per month???

Why would anyone want to pay $11.97 up front for 3 months when you can get 3 months (paying monthly) for only $5.85?

The quarterly payment option costs 200% more than paying monthly! (That's not cheaper)?

@canucksgirl: Yes, exactly. For the quarterly, you pay MORE money up-front even though you are paying for a longer period! This is in direct contravention to the claim that "the more you pay up front, the cheaper the overall deal." (I'm not shooting the messenger, StumpChunkman :-) )

The quarterly billing does not make any sense whatsoever. I will leave it as an exercise to the reader to supply the simplest explanation for why this mysterious option (and the confusion surrounding it) might exist.

@Lithium Rain. I agree. The way the options are presented is far too confusing... To me, it gives the impression that the shortest membership term you can buy is one month (I didn't see the light grey "billed annually").

@STAFF, should maybe think about changing this; and present it not so much by price but by the length of membership.

3 months*
1 year
2 years

I know that people have asked if they can buy a membership for just a month, so perhaps there's more confusion with the presentation of membership options than just the price. :-)

* Or is 3 months even an option? Is this just another 1 year term that you can pay quarterly versus yearly???

You're paying for a shorter period (3 months). The monthly billing cycle is yearly. Calling them quarterly and monthly payments is what causes the confusion I think.

The quantum mechanics of the pricing was discussed when this was initially rolled out http://www.instructables.com/community/Pro-Instructables-Accounts/

Right, but a monthly membership is charged by the year, so it has a longer membership cycle.

The payment cycles would look something like this:
Quarterly: $11.97
Monthly: $23.40
2 years: $39.99

It might be better if written like this:
3.99 per month billed four times a year
1.95 per month billed once a year
1.67 per month billed every two years

...but the way it's currently written, the implications are the same. It does cost quite a bit more, but you're not required to select that option, and that's not what's presented at the top of the list. I would think that by putting that payment option in the middle, and giving it the same exact wording that you give monthly, it would incite further investigation and final decisions as to which plan works best for you.

StumpChunkman: if the "monthly" membership has a membership cycle of one year and is charged as such, why is it called the monthly membership?

I'm not really sure why people decided to call that one the "monthly" membership. I call it that since I've dealt with a lot of people who have had issues with their pro membership, and they tend to refer to their pro memberships as either monthly or quarterly. I suppose monthly got picked up for the yearly since it's first in the list, but I can't really see a good reason (including that one) why it's the case. Perhaps someone decided to one day, and everyone else copied that person? Perhaps it's a rollover from when instructables used to have a monthly payment option? Maybe it's a problem in inference, where someone skims the payment page, sees quarterly and one time payment and just assumes that the initial one must be monthly. Not really sure, but I suppose I'll start calling it yearly now since that's been pointed out to me. Thanks.

@StumpChunkman

Okay, fair enough - I was under the impression that it was official nomenclature, but the page doesn't actually call it that so that must not be the case.

To me, half the problem is that the table is not set up so that the consumer is not comparing the same units - you compare month:month:two years. It has the feel of a shell game. It has been repeatedly pointed out that this comes off as either very sloppy or deliberately obfuscatory. :-\

I personally agree with you. I think the units should all be the same. I also think that the sub-text should be much more prominent. But that's just me (and I don't work there anymore...kekeke).

(Ahh...I wondered, but figured you must be back on as a remote employee or something. Hope you're having a good time with whatever it is you're doing now! :) )

By the way if it is done as I wrote above...
1.99 = 1.99 per month
3.99 quarterly = 3.99 / 3 = 1.33 per month
39.99 2 year = 39.99 / 24 = 1.66 per month

The quarterly would be best price - still whacked out.

If the 2 year price was set to 29.99 then it would be 1.25 per month and that is the best deal. The people working on this pricing model need to pay attention and repair this issue quickly or the user base will become upset even faster.