May a local shul charge out of town guests a fee for high holiday "seats"?
Money and religion often makes for a volatile, albeit necessary mix. Jewish law requires that all members of the local community contribute to the building and maintenance of a shul, school, mikva, library and the like regardless of the amount of usage they make of it. In fact a minority can force an unwilling majority to allocate funds for such a purpose - despite the protestations of the majority that they are happy to say, pray in somebody's house(or not pray at all). While the Jewish community no longer has the coercive powers to tax its members guidelines developed over the centuries are still applicable on a volunteer basis. Recognizing that while each member of the community can benefit equally from services provided but have different economic means, Jewish law has generally allocated half of basic synagogue expenses on a per captia basis and half based on ability to pay. The costs of synagogue "extras" such as fancy windows or a beautiful social hall should be borne mainly by the wealthier members of the congregation.
Rav Moshe Feinstein (d.1986) ruled that one is not allowed to leave a synagogue with its large dues structure and establish another shul with cheaper dues. This ruling applies, even if the nusach (style), tunes, or even ideology of the new shul is more in line with its founders (provided the established synagogue practices do not violate Jewish law).
In theory a community is within its right to deny non paying (well to do) members the right to daven in their shul, not just during the high holiday season but all year. However before implementing such a harsh policy one must determine if overall religious observance will be enhanced thereby, taking into consideration such factors as to whether alternative "free" services are available.
However the requirement to pay "membership" dues only applies to residents of a community. In keeping with communal hachansat orchim (welcoming guests) visitors should be welcomed without expectation of fee. This approach, I believe, should be adopted worldwide so that membership in one shul entitles one to seats in any other shul. Imagine what that would do for the sake of Jewish unity.