A few of the prices that nomad001 list are high, but in general it is a spot-on assessment. (i.e. St Mary's Cathedral admission only costs $6, but the priest asks to be tipped for everything, so you could easily spend $15 as nomad001 describes. A guide is not required for Simiens.)
wilddog, you are correct that Ethiopia is still relatively cheap. But it has become much more expensive in the past several years, and the budgets in older guidebooks are no longer appropriate.
$100 for a car is a good deal in Ethiopia. Budget backpackers do in fact pay this price, but group together to share costs--with 4 people this is only $25 per day.
nomad001's assessment about "having to bite the bullet" is also correct. Getting a group together to share costs is not always easy. It is not like going to Arusha, where you can just show up, and things fall into place.
There might not be "poor" backpackers, but there certainly are "miserly" ones. I take wilddog's being "budget-conscious" as meaning you see everything possible (within reason) but as cheaply as possible. Sadly, there are more than a few backpackers who travel half-way around the world, then forgo an incredible experience because it costs a few dollars more than they expected.
Peace,
BB
