First, tell us where you live. Resources vary with locale and it's difficult to give specific help without this info.
If you don't have health insurance you will have to give your history when applying and, yes, Cluster will be a preexisting condition. Whether it's excluded depends on the company.
First option: search your local medical resources for no or low cost care. Inquire at the social services office at your hospitals (larger the better); ask at your local health department, at the United Way organization office.
If you have access to a GP who will negotiate fees with you AND he is open to accepting MEDICAL literature which we can supply, he could learn how to treat Cluster and be the source of the meds which help the most.
Explore the buttons (left), starting with OUCH, where you will find many useful leads; ditto for the top of one of these message sections where there is a collection of messages on self-help. A good self-help book:
HEADACHE HELP, Revised edition, 2000; Lawrence Robbins, M.D., Houghton Mifflin, $15.
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Learning what you are dealing with is critical.
Cluster headache.
From: Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

or

(Orphanet Journal of Rare Diseases)
[Easy to read; one of the better overview articles I've seen. Suggest printing the full length article--link, line above--if you are serious about keeping a good medical library on the subject.]
Leroux E, Ducros A.
ABSTRACT: Cluster headache (CH) is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes) of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye). It affects young adults, predominantly males. Prevalence is estimated at 0.5-1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name) in bouts that can occur during specific months of the year. ALCOHOL IS THE ONLY DIETARY TRIGGER OF CH, STRONG ODORS (MAINLY SOLVENTS AND CIGARETTE SMOKE) AND NAPPING MAY ALSO TRIGGER CH ATTACKS. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH IS ASSOCIATED WITH TRIGEMINOVASCULAR ACTIVATION AND NEUROENDOCRINE AND VEGETATIVE DISTURBANCES, HOWEVER, THE PRECISE CAUSATIVE MECHANISMS REMAIN UNKNOWN. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms) has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments) and to reduce the number of daily attacks (prophylactic treatments). Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the hypothalamus and greater occipital nerve stimulators have been tried in experimental settings.THE DISEASE COURSE OVER A LIFETIME IS UNPREDICTABLE. Some patients have only one period of attacks, while in others the disease evolves from episodic to chronic form.
PMID: 18651939 [PubMed]
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Give us a listing of what you have tried to abort/control your attacks. How much, how long used, results, etc. No need to reinvent the wheel by suggesting approaches which you have already tried.