1) Internet, or GYM$$$, this takes time as there are way more scammers on the net than legit (SPAMMERS = INSTANT SCAMMER)
2) Depends what and WHO you buy from, you can easily pay 2-3 times with one versus another
3) Strength Anavar is popular, size, oh brother ("TEST IS BEST" is famous but some wont do test until they are 60, almost all roids are for size/strength because they are for people with wasting diseases/anemia).
4) Best, in general is just low dose of your choice item, there are SO many, but test is still backbone for almost everyone. If you do no orals then test front loaded, plus your after cycle therapy. Deca etc can be detected (drug test) up to 18 months, and is HELL on recovery unfortunately, only good for people that need Deca for what it does for the joints. I can go on and on, there are just too many to talk about.
5) Side effects should be none to mild if you are not an idiot OR are just one of those people who react poorly to something, some people do Deca ONLY just fine, others get limp dick even stacked with test in common proportions, after a mere 2 weeks. Gyno is the biggest concern, there is deca gyno as well, gyno in general is the most common side. Injecting more often to create steadier blood levels will help with this, not using tons of it the first time will help, and you dont need tons the first time anyway. 300-500mg a week.
6) More effective for long term, injected! Orals are short term, all but one are hard on either liver/kidneys (arguable how much etc etc), gains are not kept well by oral only people, as a general rule. Recoup stuff is oral however.
7) Most people who dont eat right are those same people that bitch "I lose all my gains when I come off cycle wah wah", that plus any water retention thats lost, appear as lost gains. Diet is the biggest sin of everyone natural and otherwise.
8) Cycling means doing say an 8 week stint, and then going off for 8 weeks or whatever, the general rule for people is time on = time off, obviously the bigger guys dont follow this and are often year rounders (there are tricks). Stacking means simply using multiple items at the same time, for synergysm or individual purposes, like someone who insists they need deca, or they need EQ, along with thier test, etc
9) Small doses work, if you dont go "too small", 150mg test enathate per month isn't going to do anything for you really, thats what many 'test therapy' people receive. Small doses in the 250-500mg per week range for a newbie, absolutely, and can even provide good gains for already large people. There are no reasons to use large doses early on, supposedly 1g of test a week loads something like 76% of the AR receptors, but there are no more gains to be had for a first time user who would use a large dose such as that, and even many experienced people do not go much over this, a near 300 pounder I know doesn't go over 1g period, and he started out tiny. I'd aim for 400-500 first time, front loaded and injected twice weekly, even though its not neccessary, steadier blood levels = whup ass.
10) Yes, if you dont take time off not only do gains slow down but your nuts will generally shrink if your using something that plays with natural test levels (most everything), long term deca = castration. This is because your body sees all this test and decides finally it doesn't have to make its own anymore, people use cruising periods for this reason, with low doses of test and thier clomid/nolva etc therapy, and often HCG throughout the cycle. However when coming off cycle cold turkey some people get sick, some people immediately claim to lose thier appetite and thusly WASTE alot of the time and money they just took in going through thier cycle, some people take awhile to come back to 'normal' as far as thier nuts and thier mood, clomid gives some people 'the blues'. This would be 1 good reason why some people taper off (since essentially that is what year rounders do), if you did so though dont do it as part of your regular 8 week cycle, tapering should be an additional 4 weeks or etc depending how long you were on for etc