Yes, it had occurred to me that storage could be an issue with this one.
By the way, do you know any good resources for finding good but affordable copywriters?
Still keen to read others' thoughts.
Looking at your specs, I don't necessarily agree that you'll need $25k minimum. It seems pretty simple to me too; $1k-$3k for the right person seems right to me to get you your beta then another $1k for bug squashing and $x/mth for maintenance.
What I don't get is that (a) you aren't the developer, (b) you aren't wanting to write copy, and (c) it doesn't seem like something that needs a salesperson making calls, so what's your role? Rhetorical question really.
$600 is really only a day or two's work for a professional developer. Depending on where you're at, you could spend double that just nutting out the exact requirements.
That said, as my first line was trying to allude to - it's horses for courses. You can go a lot cheaper, or a lot more expensive depending on what you're after.
If you have the right contacts, and you want something whipped up, $1-2k might be more than enough.