There will be 262, 8 million beam in total accoridng to coingecko. com... current supply is only about 3,2 million coins... if this coin will once have 1 billion market cap, the price will be about 4 euros when all coins are mined. I think, 10 billion marketcap are realistic as a long term price target if this coin is successful...
Haha, 10 billion market cap

. Be more realistic, if Beam will have market cap like ZCASH it would be a success for Beam. So 1$ for Beam is a fair price I think.