Attending a conference with self funding and no publication
Firstly, congratulations on getting your poster accepted. If you don't go, I hope you are able to find someone to present the poster on your behalf (this is actually quite common). 

In terms of deciding whether or not to go: it depends on your situation. 

Some things you should consider:


Your financial situation and how much the cost will be. On top of the flights, you need to pay for registration, accommodation, meals, a travel visa (if applicable), and local transportation (e.g. to and from the airport).
Your career stage and future goals. Are you planning to stay in the field? Will you have future opportunities to attend similar conferences? This affects how valuable going would be to you. 
How much networking you will be able to do. Do you know other people attending the conference? If you don't know anyone, it can be difficult to network. But if you know someone there (e.g. your advisor) who can introduce you to people, that can make things much easier. You should also have some idea of who you want to network with. I will sometimes decide whether to go to a conference based on knowing who will be attending and who I want to network with.


Your advisor will know your situation better than I do and can give more specific advice. So, if you are uncertain, you should talk to him more about it.