I am sorry for naïveté.
I found a workshop that fits my research and I want to submit a paper to the workshop. The problem is that the location of the workshop is far away from my hometown and I don't have funding to cover the travel expenses.
Do you think it is obligatory to visit the workshop (conference) and to give a talk in case the paper is accepted?
Personally, I have only seen conferences which require every paper to be presented on-site. Most conferences explicitely state that paper will not be published in the online proceedings, if the authors do not present their paper. If this is not stated on the conference's website, please write to the committee.
However, I recommend you to find a different solution. Discussing a paper at a conference is a very important part of your scientific career since you get in contact with other researchers. If you encounter financial difficulties, you can write to the committee and ask politely for a waiver or reduction of the fee.
The point of a workshop is to generally meet with other people and talk about your work with them.
For that reason, workshops with peer-reviewed papers typically expect all authors to appear to present their work---even more so than is typically the case for conferences. In many cases, it is in fact strictly required, and papers will be officially unaccepted and removed from the proceedings if nobody appears to give the talk (IEEE, for example, requires this of all of their sponsored meetings).
In certain extenuating circumstances, such as illness or visa problems, some organizers may be willing to arrange for a talk to be given remotely. Likewise, larger meetings in some cases will offer scholarships that can help with the expense of attendance. If you just don't want to go, however, then you should submit to a journal rather than a workshop or conference.
The best option is to contact the academic committee of the conference (by email) and ask them directly.
Some conferences allow the author to publish their work on the proceedings without the presence of the author on the conference. However, in many cases you will need to pay the registration fees.
I believe that is highly recommended to go to the conference to participate in discussions and receive feedback about your work, but is not obligatory in some cases.
