i would go with an H&R 20 or an old sears or monky wards off brand single shot. i really wouldnt go 28 maybe 410 if you found one. my dad has an old sears 'ranger' brand bolt 410 its a good shotgun made by savage stevens. most of the old private label department and auto store cross brand guns were made by quality makers, maybe the finish and wood was a bit cheaper but thats it.
i lucked into about 50+ boxes of 20 ga federal hi brass game-shok in 4,6 and7.5 one nite at walmart at $1 a box. a few 12 and 16 ga as well. the cheap bastage in me just would not let it sit and i would regret it later. i bought all they had. same stuff at wallys now is $7+ a box. even their 20 and 12ga 100 rd 'value' pack is 23.99$
this caused me to eventually buy a 20 ga shotgun just to shoot it ! now my 870 youth with short stock and 22 inch barrel is my favorite for upland game. swings up so fast. and light recoil. as soon as i get the money i will acquire a nice superposed or possibly LC or Parker SxS in 20.. win 21 just out of my $$ range.
my barn gun is my great, great, grandpas damascus Parker double in 12 ga. he was too cheap ( he came from Scotland) to shoot it much so he would rattle the barn door with the barrel and the dings in the damasacus prove it. but its been in the family 5 generations so its not going anywhere. he was a chicken farmer in Hollister CA late 1890s-19-teens. at least he had good taste in guns