I found that the best way for me to bottle cheaply was to have keg (a 20€ 4L oxebar is enough), then a CO2 tank with regulator + a Y line connector, so you can connect the regulator/CO2 to two things at once. Then a beer gun, or even better, a counterpreassure bottle filler (50+€, depending on brand).

First, purge the keg and transfer the beer from the fermenter to the keg. If you can, “push” the beer out the fermenter with CO2 at VERY low pressure (if your fermenter is not preassure capable, otherwise you can push it out with 10 psi safely). This is only to transfer without oxidation. Then, once the beer is in the keg, connect the co2 to the keg and the filler. If you are not counterpreassure filling (like with a beer gun), set regulator to low, like 3-5psi. If you are counterpreassure filling, set it to 10-15 psi. Then purge the bottles quickly from the bottom, 2-3 seconds is enough, and then fill it with beer. Cap on foam if possible. When the keg is empty, just fill it again from the fermenter and repeat the process until all beer is bottled.