I would get a rope for $10 they go for about double that for 10"ers in my area. As far as food smaller bichirs should be fed bloodworms, bring shrimp, blackworms, shrimp pellets etc…, smaller things that they won't have any problem fitting in their mouth. As they get larger you can start to introduce tilapia massivore as well as other hikari pellets, earthworms, silversides, catfish, etc.., You can feed the pellets when they are small, but you have to cut them up very small to prevent choking. I personally have fed beefheart to my smaller polys to give them a little boost in growth. My personal take on it is that it helps with smaller polys a lot. I wouldn't feed it as a staple, but more of a common treat. It helped boost the growth rates of all my grow outs. Some people will say that it shortens the bichir's life span and that they will die because of the stuff in bee heart. That is partially true, but only if fed as a staple. I would only feed as a common treat and once the poly gets to 5-6" quickly convert it to another food. For my small guys I would feed everyday and sometimes at night if I had time. I would alternate days and feed bloodworms, brineshrimp, and shrimp pellets. Sometimes I replaced shrimp pellets with very small pieces of massivore (which helped their growth rate as well). I would then feed beefheart at night if I had time (only fed it maybe 2-3 a week).
Anyways post some pics of so we can see this little guy. As far as price $30 isn't that bad for my area that's actually more than a steal for me. The ones I see are about $60 for a 4-5"er.
to get fish like delhezies for cheap around here 7 inchers cost around 100 dollars 
