This is going to sound crazy, but that's why I'm here...
I would not start out with just a floor pump, why you scream? If you're on a limited budget you need to have a pump you can take with you when your riding, a floor pump will do no good staying at home while you try to fix a flat 10 miles from home. There are not many good mini pumps sad to say, the only really good one so far is the Lezyne Road Drive long version for high pressure road bike tires and the Lezyne Alloy Drive for high volume MTB and hybrid type of tires, they make two other shorter versions of both pumps don't bother with those.
If money is tight you can get a cheap floor pump called the Bell Air Attack, it won't last long, maybe 5 years, but the time it breaks you can afford to get a decent one. If you can afford a nice one now the Topeak company makes a line of really nice ones for not a ton of money that will last at least 20 years like the Joe Blow Sport III.
On that same note a pump isn't going to be much good if you can't fix a flat, or don't have a flat repair kit and a spare tube with you. So you need to learn how to fix flats on the road, you need a patch kit and spare tube as mentioned. You need a set of quality tire irons, I personally like the Soma Steel Core levers because they won't break but won't mar rims up like all steel will do because of a plastic outer shell, the best plastic levers is the yellow Pedro's levers. Easiest patches to use is glue on patches, but the glue tube can dry up. I use Park Super Patches, these are a glueless patch and if done correctly they will last the life of the tube, if you want to know how to use the glueless patch let me know it's not much different than a glue on patch, but only the Park brand works for the life of the tube, other glueless patches last about a day.
If you mechanically inclined you may want a mini multi tool, like a flat this is case you break down or need to make a simple adjustment on the road, but it can also be used at home, I use my mini tool at home more than I use my dedicated bicycle tools because it's in the seat bag and I don't have to rummage through my tool drawer to find a tool.
I noticed you got a helmet, great, but there is another safety factor you need to seriously consider if you'll be riding on roads shared by cars. Due to distracted drivers you need to get yourself visible. You need is the brightest tail light you can buy, at this time the brightest one is the NiteRider Omega 300, this thing puts out a startling 300 lumens on the highest strobe setting, compare that to a car tail light at 88 to 100 lumens. Why so bright? because you have to make up for the size difference of a car tail light vs what you can carry on a bike. This light can easily be seen in broad daylight from a mile away.
The other safety consideration is a front flashing strobe light, there are lot of good ones on the market so take your pick, but what you want is one that can serve double duty, one that can strobe in the daytime and one that can be used as a headlight at night. You need at least a 400 lumen strobe capability, and around 1,000 to 1,200 lumens for a headlight. If you are a very alert car driver a strobe during the day may not be that important if you are watchful of cars coming at you, but it could help regardless, and will help if you're riding on a dim, foggy or rainy day. Raveman makes a good line of lights worth considering. You could try a cheap Amazon Chinese light, but these won't last long, they don't put out even half of the lumens they say they will, nor will the batteries last even half as long as they say they will, but they are cheap if you're on a budget, just pick one with the highest and has a lot of reviews.