I guarantee it will cost more for you to synthesize than for you to purchase bulk from China but better yet just don't do either.
This chemical is garbage and we don't need more of it flooding the market.
Not to mention if you aren't even able to find a synthesis route without help then you likely aren't near experienced enough to actually perform the synthesis.
We do not allow synth discussion on Bluelight. We're here for the purpose of harm reduction, and advising anyone on how to synthesise 25i-NBOMe is about as far away from that purpose as you could possibly get.