Do plug in pest (insect) repellents run up electric bills?

I'm leaving for the summer in 4 days and I just noticed ants (in pantry) and springtails (on windowsills, bathroom, kitchen) in my home two days ago (apartment on top floor of an old home-the bottom is used as a bar/hangout area for the landlords son.) Last night I just saw a cockroach for the first time and it's feces on the pantry floor. I cried a little bit because I've never, ever had bug problems and these three issues just showed up within two days of each other. Im freaking out, my landlord is going to bug spray, but I'm going out of town for 3 months, may-july and I'm scared my house will be overrun when I come back. So, I'm wondering if i could buy an ultrasonic plug in bug/pest repellent and if it will do anything. I'm also wondering if it will run up my electric bill (and extra $5 a month isn't bad.) Advice? Thank you!