Only spent about one week in Turkey, and less than 2 weeks in Iran, so mostly just rode through them using highways... (Izmir-Konya-Cappadocia-Bingöl-Tatvan-Dogubayazit-Tabriz-Tehran-Qom-Esfahan-Yazd-Bam-Zahedan-Mirjaveh)
this is why I probably don´t know these countries very thoroughly. And this was in Oct/Nov 2007, so things may have changed.
But appeared to me, that Iran was generally almost as cheap as India (which is dirt cheap, especially food & accommodation!), but the cheapest places to stay in Iran were sometimes real ratholes (often the case also in India), so for us, it was better to pay a little more.
And Turkey was more expensive. Fuel in Turkey was in fact more expensive than in Western Europe, so that is something!! And at least those roadside hotels & guesthouses we popped into, werent very cheap, somewhere around 40-60 euros per room. In Cappadocia, where there was lots of places to stay, was much cheaper. Food in Turkey was cheap by European standards, but not like Iran and definitely not like India.