Developing a project, even a small one, can be expensive. From when I started working on the Open Journal Matcher in earnest (in January) to when it was more or less complete in its current form (in the beginning of October), I probably spent about $1000 of my grant money. To me, this is a lot of money. It is definitely more than I would have been willing to spend personally. Needless to say, I am grateful for the funding.
The OJM is never going to be self-sufficient. It exists to help others; but unfortunately keeping it online is not free. Ultimately, I think it can be very cheap over the long term, so as to be sustainable. But the upfront development costs were considerable, from the perspective of my limited pocketbook. I think it needs to be pointed out that this kind of monetary hurdle prevents many worthy and interesting projects from ever being realized.