My ad ran site-wide for 2 days last December (total $40) and saw 331,901 impressions but only 148 clicks (CTR of 0.044%). Since it was advertising a free app which itself makes money through advertising, each of those clicks (and the far fewer conversions) were worth a lot less than what I paid for them.
I bet Reddit advertising works great for expensive physical goods (like watches, Amazon affiliate links, and Not Safe for Wallet links I see advertised a lot) where you can afford to spend a few dollars per conversion in advertising, but it does not seem to be a very good choice for apps.
For example, I followed the link to /r/selfserve and saw someone complaining: "$100 for 13,000 impressions is a rip off. I've been advertising for years online and this is lowest I've seen by a mile" and following up with a comment saying "$100 buys 150k impressions anywhere else". At that price you're going to be getting low quality impressions wherever you buy, and if he's never seen a CPM rate like that before he's got a very limited experience in his years of advertising. In my world, as long as clicks are well targeted I have no problem hitting an eCPC of $1, and I spend a hell of a lot of advertising money getting those clicks.
No doubt people who actually work in advertising and know what they're doing aren't talking about it online, whereas the people we hear from are those who spend a tiny amount (normally $30, much too little to judge on) and don't necessarily understand too much about what they're doing.
That said, I don't know enough about it to have any decent thoughts on the subject, I've spent a few bucks just to see how the booking system works but never put any effort into getting results from it - I didn't like the system too much and wasn't optimistic that it could give good results. So on the one hand, this comment is just uninformed complaining about others, but on the other, I've probably spent more than most people who complain about Reddit advertising yet I know I don't know enough to judge it.
Note to OP: Most of this comment was about the overall situation not you. That said, I do think that spending $30 and coming to any conclusion stronger than "it's not worth my effort to try and find out if Reddit advertising can help me" is based on too little information.
Edit: To add some more general feedback about Reddit advertising, my feeling is that right now they're the worst of both worlds (self-serve and account managers). Most platforms buy me lunch to ask what I want to do with them, some, like Facebook, make me book in manually, but with that manual work comes the added value of the options they give - with Reddit you have to do it all yourself while getting hardly any flexibility. (And even with Facebook, I still have an account manager, an account strategist and a technical account manager, all three of whom are reachable on mobile any time they're needed even outside office hours.) I get that Reddit self-serve is still young, and I've heard talk of improvements on the way (such as paying CPM rates), but right now it just feels far too amateur to keep my attention - from the selling all the way through to the reporting - despite the fact that I use Reddit myself.
That's what it came down to for me, I'm not optimistic that I'll ever get great results spending $30 a day advertising a $2 app to Redditors.
But yes, the $30 / 1 day data isn't large enough to draw any real conclusions.
It's your business and one primary reason you are where you are is that you've used your "nose for business" along the way to make judgments - judgments, I'm sure, that in many cases could be classified as "Not enough data to make a conclusion" yet you made a conclusion, were right, and here we are. If you think that the data tells you that it's not a worthwhile place to advertise, then go with that. The statisticians and internet commenters with nothing at stake will always ask for "proof" (in terms of trial runs, # of impressions, 30 days, etc) but never forget that you are where you are because of your decision making ability...
And just to be clear, I'm not trying to disrespect/discredit/etc corin_'s comment - mine is just a general comment meant to say that "educated intuition" is just fine when you are a business person running a very small business.
My bigger point was just that while individuals can make these judgement calls, their experiences shouldn't necessarily be looked at by others. The problem with blog posts like these is that too many people will look at them and think "so that's the CTR/eCPC/etc. price I can expect" or "those results are what I can expect", without realising that at a $30 spend it's pretty irrelevant to them.
We're doing another round next week, so it'll be interesting to see the download/sign up conversion.
I don't mean to be harsh, but your results don't really say anything about the merits of advertising on Reddit. Ads can impact purchases long in advance, but more importantly you can't expect single touch ads to work! Most users ignore an ad until they've seen it multiple times. I suggest you read more about effective frequency/advertising frequency.
From personal experience, I can tell you that even good products with good ads usually start off as losers, then increase their return as they reach their full audience multiple times. Once you've achieved saturation in that channel, your ROI levels off and then begins to decline.
Honestly - and I say this for the benefit of anyone who thinks this test is meaningful - that $30 would be better spent on a textbook about the basics of online advertising.
Your 2.34% sales rate is totally wrong because you can't track the route of the traffic, but I would be pretty happy that conversion rate. You have no price in your ad (to gain clicks) but I am sure lots of people feel $2.99 is kind of expensive for something they don't really feel they need (i can just visit reddit for free).