I'm typically pretty careful with my investments. I haven't really had any major terrible investments. Most people are clear about what their services are and I haven't ever ran into anyone that wasn't able to back it up. I would say the worst problem I ever ran into was a content writer. Before I personally got into content writing I tried to build a "team" of writers. When I did this I ran into an Indian that promised me he was good with English grammar. His emails looked pretty clean. When I got the content from him I ran it through copyscape and it was a deliberate copy of another website. I confronted him about it, and he tried to fix it. The problem was that the content was not in good grammar at all. I spent several hours correcting mistakes. Needless to say I gave the idea up that you could really outsource that type of work effectively.
Years ago i paid something like £40 for 500,000 hits, i was very new to things at the time so didnt really know what i was doing, they said the traffic would be sent via popups popunders etc over a 1 month period. My counter did show that i had received the hits but i didnt get 1 sale or any interest at all, im pretty sure my site was just on refresh somewhere and i wasnt receiving real visitors, i then researched the company and was everywhere that it was aa scam, I should have looked into it properly first!
Spending money buying books after books but don't spend the time to follow the instructions from any one of them.
Here's a little list 1. Content writer, writing a travel article about a place where it was obvious she hadn't been. 2. Paying for a certain number of hits and the hits being crap 3. Anything to do with SEO - I bought an SEO package with my hosting to be told we'll monitor it in a couple months and then to be told - its all good - I guess he checked that I had Titles!
I have tried yahoo answer marketing from people and i have spent lot in it but i never got enough traffic using it
As it was an "investment" in my online education and business development, can't really say that any investment was the worst. It's just that some didn't return on investment that I had hoped for. Consequently, lesson learned.
Fortunately i did not have mistake on my online marketing as i know most aspects of this kind of business.
I tested some offers on Fiverr for traffic just to see if any good. Worst money spent ever - no traffic at all as I more or less expected but you need to try these new sites or you'll never know.
I bought around 4 domains to make money with and finished wasting $80 domains and $40 hosting -> $120 wasted. I also spent some money (I don't remember how much) and finished losing a $500 worth twitter account because of a small mistake (won't tell) I made also lot of small mistakes, like dealing with bad people and losing some $$ with them.
What have wasted the most is TIME not money. When I started on IM, I used to buy or download free almost anything that seemed interesting. Most of all those ebooks where far away of what I expected. Sometimes I was able to get my money back, but the time I spend reading them is something that can not be refunded.
I am not sure how much I have spent, but I have only wasted money on several domains over the years, maybe one or two a year. Not huge losses, but I have learned that being a webmaster or an internet marketer entails a HUGE learning curve.