I suggest the Music Studio on Harrison Hill.
You can read an article about the Cooperative Teaching Artists on Neighborhood Notes.
Similar to grocery or housing cooperative members, [Cooperative Teaching Artists] offer time and money on an equivocal scale, with discounts or benefits shared equally.
“Music educators, like many artists, often work in seclusion, which has a huge effect on their teaching methodology and pocketbook,” says founder and director Daniel Fitzmaurice. “One of the main functions of the Music Studio on Harrison Hill is to create a community of musicians who share the financial and creative energy of teaching—large, shared spaces and instruments, collective advertising, cooperative professional development, and joint musical collaborations.”
Also? The Portland Ukulele Association meets there on the first Sundays of the month.
(Full disclosure: I’m a member of St. David of Wales Episcopal Church, so while I’ve never [not yet?] taken lessons from any of these folks, I’ve had the opportunity to hear most of them perform. )