First off, you should cast the spell yourself. Not only will it be free, but you will know it actually was done. If you are having trouble with casting spells, take a look at this article. It (hopefully) has everything you would possibly need to know concerning spell casting:
Now, if you do choose to hire someone to cast the spell for you, I think it's reasonable that they ask for money, as they are providing a service for you. The price may also fluctuate depending on the materials they use, such as herbs and candles, as they will need to be compensated for those materials. Even then, $245 is asking way to much. This person is likely a scam.
To assure that you are not being scammed, I recommend paying the cost of the materials up front, and then requesting a video of the spell being done. Once you receive the video, pay the rest of the agreed upon price.
At any rate, be careful of people offering to cast spells for you. Although there are some genuine people out there, they are unfortunatly few and far apart. Be mindful of not being scammed, and I wish you the best.