Arranged by cost & effort:
1) Take your basal body temp every morning
Take your temp at the same time every morning - before you get up to pee, etc.I used an app on my phone to keep track of my temps but you could also do it on paper. I set a special alarm on my phone so that I stuck to the schedule even on my days off.
This is free and easy as hell and it tells you TONS about what is going on with your cycle.
You can also chart your cervical fluid to see when it is all egg-whitey and fertile.
2) Instead SoftCups
You can get these at the drug store on the same aisle as the tampons.
Put one in right after sex to keep all the nice sperm in place.
Also, if you can get your partner to agree you could get him to jerk off into one when you don't have time to have sex or just want to increase your odds. I call this carpet bombing. (The hardest part of getting knocked up, for me, was not having enough sex, but utilizing my partner's 'private time' we were able to double our coverage.)
This costs about $10 and can't hurt, right?
Melissa Light is amazing and she specializes in fertility. This is something that both of y'all could do, or just you.
This is about $60 a week, so it's a bit expensive, but for me was worth it.She will also give you special herbs - but I passed on those as I wasn't really sure how they might impact my other meds.