According to GIRM no. 73, during the Offertory “t is well also that money or other gifts for the poor or for the Church, brought by the faithful or collected in the church, should be received. These are to be put in a suitable place but away from the eucharistic table.” That doesn’t, strictly speaking, cover tied bundles of Mass intentions, but I think the general principle is that things necessary for the Mass, as Benedictgal quoted above, should be at the altar, while other things, no matter how piously intended, should not. Things like flowers are perhaps a different case, as they are intended to give glory to the altar by their proximity, not to take glory by proximity to the altar. So no bundles on top of the altar (sorry Malphono), and, I would think, no bundles under or at the foot of the altar either.
I have to agree with malphono in that money and gifts for the poor are totally different than Mass intentions. While I do not believe that they should be placed on the altar, I do not see any reason to object to them being on a small table next to the flowers. Of course, if there are any specific rule that this should not be done, then it should be followed. I recall seeing squares of plexiglass placed under the benediction candles to prevent any wax drippage on the altar cloth. There is no mention of this being allowed but common sense tells me that this is OK.