I disagree. You can have low-quality and safe together. Of course, that's not normally the case, but it's possible. (it can be homemade and crappy looking, but still be safe)
Electrical tape shouldn't hurt you, so long as you aren't melting or burning it. Since this is going into an anal orifice, I assume you'll put a condom on it. I can't think of anything in electrical tape that is capable of passing through a condom, so you should be okay (please correct me if I am wrong).
Now the question is, what are you using for the core of your device? Socks, rope, plastic and rubber stuff should all be just fine, covered with electrical tape. There are plenty of squishy low quality things to use for a core that can't hurt you.