First, don't record to cassette. Go digital from the start.
What you charge should depend upon what kind of audio you are putting up and how it is going to be served. Downloads don't count.
Real sucks and is a very bad choice. MP3, WMA, AAC, and ASF are the best choices for formats. AAC is too expensive to implement though.
ASF is good, but more complex than WMA to implement. WMA is drop dead simple. For an (incomplete) example see maven3d.com at
http://maven3d.com/en/experience_it.asp?PID=1
The source is drop dead simple. You can create the files with the Maven3D Professional trial, other programs, or you can get the encoder from MS.
I still have to add in some stuff to let users choose either Flash or Windows Media, but I'll get to that in the next week or two...
Flash is good for MP3s.
If you need streaming, i.e. for large files, then ASF is good.
I find Quicktime to be complete garbage as it doesn't work well, just like Real.
For price, for Flash, you need to develop the interface - and that can vary. $25~$1,000.
For WMA price - cheap. Very easy to do. $10~$200.
For recording and editing... that's where the money is. For 40 minutes of recorded audio, you'll spend at least 2 or 3 times that editing it, minimum if the content isn't perfect from the get go. $20~$300 per hour. Since your asking... keep it low.
Speaking of which... 40 minutes is a LOT of audio content to put up in one chunk. I hope it isn't one chunk... Need more info.
I'd do recording and editing at $30~300 an hour depending on the content and whether I liked them. For programming, again, depends on how long the content is, the target audience, server specs, etc... It can get nasty. $40+ is not unreasonable.
The content at maven3d.com is immensely complex and if someone needs to ask about the price, they can't afford it.
Also, factor in studio time if you need it. That goes for $50 to $300 per hour on average. If you have the equipment, factor in those costs. e.g. I'd charge cheap if they just need a mic, but if they require a studio (which I have access to), then the price goes up a lot.
In short... narrow down what you want to do...