I see this from time to time, and it makes me smile. Some people think there's no way to prove that the Earth is round without going to space. There is a plethora of evidence to tell us the shape of the Earth, and you do not need to go to space. 20 cheap (probably free) ways to test it out for yourself:
1) Observe an object disappear into the distance... does it vanish bottom first?
2) Observe that moving to a higher altitude can make the bottom of that distant object reappear
3) Watch the sun/moon rise and set. They clearly dip below the horizon and come back on the other side
4) Measure the angular size of the sun/moon as they traverse the sky
5) Triangulate the location of any star using 3 people in 3 different cities
6) Take time-lapse photos of the night sky in the northern hemisphere and the southern hemisphere. Notice that the stars appear to rotate in opposite directions
7) Look up the location of the ISS in the night sky and go and see it for yourself
Look up the next lunar transit of the ISS and take a video of it for yourself (requires a telescope or good zoom)
9) Measure the rate the moon/sun move across the sky and compare that with round vs flat models of the earth
10) Measure the angle between eye-level and the ocean at different altitudes... does the horizon really rise to eye-level?
11) Notice that the moon is upside-down in the southern hemisphere
12) Try to make a semi-accurate map of the flat earth using commercial direct flights between cities to approximate the distance between them.
13) Watch a shadow climb a tall building at sunset
14) Drive around your city and look at every satellite dish you can find... what radio source are they pointing towards?
15) Take your own satellite dish way out into the middle of nowhere and watch TV with it. Where do you need to aim it for this to work?
16) We missed Venus in 2012, but watch Mercury transit the Sun November 2019. Then figure out how Venus and Mercury must move within the "firmament" for this to be possible.
17) Go see a Foucault pendulum or make your own
18) Take the compass bearing to the sunrise and/or sunset during the next equinox
19) Pay attention to all the tropical storms this summer. Which way to they rotate? See the pattern?
20) Notice the relationship between the phase of the moon and it's location in the sky relative to the sun.