The main difference between SEO (search engine optimization) and PPC (pay per click) is that traffic coming from SEO is free (organic), while traffic generated from PPC is not free. You should pay for each click.
It depends on your budget "how much you're going to invest in online marketing"?
If you have low budget then SEO is the best option
on the other hand, if you have a good budget then PPC is a great option.
Both PPC and SEO are good for online marketing but SEO is more preferable than PPC because SEO is the cost effective method, provides long term results but it is a slow process.