Ive had my Dipole tween two trees for years now. Next door always
been rented and Mine has been there since the previous Owner let me
....[snip]....

I'm not sure how cheap you wish to stay, but I would suggest a couple
10' stackable sections of 1"dia steel masts as often available at
....[snip]....

In the USA, Home Depot (and presumably Lowe's, etc.) sells 10- to 20-foot
lengths of pipe for the top "rail" of chain-link fences. Sometimes it
even has the swaging that allows one to fit in the end of another.
Remember that all such pipe masts will need guying.
--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
NRA Life Member & Certified Instructor for Rifle, Pistol, & Home Firearm Safety
Also Certified Instructor for the Kansas Concealed-Carry Handgun (CCH) license