1/ Who determines the price of a token at launch?
For example, the SUI token cost a few cents in pre-sale and was listed at almost $1.50 on the Binance listing
The currency team estimates the listing price, which is often low. After the listing is completed, the people who got the price before listing will try to sell their currencies here. The required liquidity will determine the price of token. If there is more demand than supply, the price will increase and vice versa.
manipulation can happen here where the currency team or anyone, with amounts such as a million dollars, can pump the price of the currency and thus create a false demand that brings more people out of greed, and suddenly you lose all your money.
2/ In your experience, is it a good idea to buy a chip the second it is listed for a profit?
It's the worst time for you to buy because it's when the whales move in to make their greedy instincts go up and you lose a lot.
If you got that token for free or because you performed a service such as participating in the bounty, then sell half of it after listing and the second half after 3 days, otherwise do not invest.