High humidity during flowering

The consequences are bud rot and an unusable harvest... BUT I understand you're on a tight budget and just getting an exhaust fan may not fix your problem (although it might help). I don't have an exhaust fan either... can't afford one... so I do what most folks here would say is absolutely heresy... I unzip my tent partially! And I open the vents as wide as I can and I make sure the fan is blowing as hard as it can without risking damage to the plants. I've figured out if I unzip most of the bottom and up the side about 1/4 of the way, the tent's temperature stays about the same but the humidity is lowered (unless it's humid EVERYWHERE)... Sometimes, I need to drastically reduce the temp in the tent and I unzip almost all of the top and then down about 1/4 of the way.... Heresy to most people - but I haven't found that it affects my grow at all other than to give it better conditions. If you've got room, there's a cheap DIY dehumidifier you can try - get 2 5-gallon buckets and some rock salt. Take one bucket and drill holes in the side (up about 1/3-1/2 way) and on the bottom... lots of little drainage holes.... then put that bucket inside the other one and fill it with your rock salt. The rock salt takes moisture out of the air and the resulting water drains into the bottom bucket which you will have to empty as often as necessary (you don't want a lot of standing water staying in the tent!).... You might try both of these things before you go to the expense of an exhaust fan... Good luck!