Estimated cost for diy biohacking
" ... you can get started for around $500 or less with a little improvisation and patience." -- How to Set Up Your Own DIY Bio Lab

The $500 is pretty minimal and you won't get much done with that -- they mention other equipment (like a PCR machine) -- and you'd need to be extremely handy to be able to build all the equipment by hand.  More likely you're looking at thousands or several thousands of dollars.

Several sites give guidance:


A How-To For DIYbio Lab Equipment
Genome at Home: Biohackers Build Their Own Labs


Getting reagents may not be easy; I don't know how readily companies sell to individuals.

Don't forget that some experiments may require approval by animal care committees etc, unless you want to be arrested for animal abuse.

You might look into biohacker collectives, which are shared spaces where multiple "hackers" can use common equipment.