bonjour, je mapele Diana
i hope you understand English as i understand French, i'm sorry that i can't write you in your language as i forgot the gramatical part.
i have experience in promoting Facebook posts/events/pages, usually this is done through Facebook Ad Campaigns and the price starts from 0.01$ (per like/share/comment) but lowers when the promotion gets popularity to 0.005$
if you are interested or have some questions i'm here to respond and help you.
thanks
hope to hear you soon.