Remember you need to tune it to your frequency.
If you don't, you're just spewing a signal all over everyone else and you'll get an FCC visit pronto.
If you can afford a 150w transmitter, there are plenty of under $100 real antenna's out there.
It may be pirate radio, but, being a good neighbor (in real life and on the radio dial) is a much better way to operate.
Honestly, you should of - or if you could of got an eBay gift card. Here's what I'm using https://www.ebay.com/itm/182592613005
Maybe on Amazon https://www.amazon.com/dp/B07NMG3XFC/ref=cm_sw_r_apa_i_YE9JEbPKPZN27 if you could shell out another $30~
That's about it honestly, eBay would be your best bet but I'll keep a look out if I find something from a reputable company/source on Amazon.