Coindesk published an interesting interview with the co-founder of a company which, for $15k, will fake your exchange volume. They basically create bots that trade tokens back and forth with each other for the illusion of significant trading volume. This helps getting listed on CoinMarketCap and can lure investors into thinking the token is very active.
The good news is that many of the top market tracking sites (CoinMarketCap, CoinGecko, etc.) are now looking for wash trading activities and ranking the different exchanges accordingly. Those who are playing with the numbers are at risk of being delisted. That is a huge penalty in a competitive environment to attract and build a customer base. This is a natural forcing function of a healthy market, pressure to discourage unethical practices.
Combined with emerging regulations that establish rules and accountability, the window for these kinds of services is beginning to close. Even those who are providing these services see that the end is coming.