How much should I save up for on a budget friendly but quite quality fixie?

for context i already have a road bike so i am pretty experienced with bikes and i want to try fixed gears, the bike that i own is actually just gifted to me and I don't want to or rather can't sell it. so from zero what should i buy?

I'm thinking maybe a 2nd hand from Facebook market might be good and then just upgrade it from there.

tho actually i had a bike i was going to buy-the ds aero costing i think 14k? but now i realize that i do not have the money for that.

for my budget, i can go from 5k to 9k? maybe